N    EUROPE 


U  R  C  H 


UNIVERSITY  OF  CALIFORNIA 

ANDREW 

SMITH 

HALLIDIL: 


18685^1901 


OF  SAN  FRANCISCO. 


*• 

oo 

3^0  .+. oQo 

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NOTES 


07   A 


METALLURGICAL  JOURNEY 


IN  EUROPE. 


JOHN  A.   CHURCH, 


ENQIHEEE   OF    MINES. 


WITH    TWENTY-TWO  ILLUSTRATIONS. 


NEW  YORK: 
D.    VAN    NOSTRAND,    PUBLISHER, 

23  MURRAY  AND  27  WARREN  STREET. 
1878. 


TO 


THOMAS  EGLESTON,  JR., 

PfiOFFS^OR  OP  MINERALOGY  AND  METALLURGY  IN  THE  8CHOOL  OF 
MINES,   COLUMBIA   COLLEGE,  NEW  YOKK, 

TI1IS  VOLUME  IS  RESPECTFULLY  INSCRIBED. 


105985 


IIV13EX. 


AGORDO  copper  procass 3 

Size  of  mineral  mass 3 

Ore 3 

Old  process 4 

Wet  treatment 4 

Cementation 5 

Crystallization 5 

Table  of  operations 6 

Treatment  by  Fusion 7 

Table  of  treatment  by  Fusion 9 

Loss 11 

Expense 11 

Improvements 11.  .18 

Theory  of  roasting 14 

Process,  cost  in  U.  8 19 

Alteuau,  works  at 94 

Amalgamation  in  Austria 43 

ANALYSES. 
Argentiferous  residues,  Hartz ....  98 

Basic  sulphate-',  Agordo 16 

Black  copper,  Hartz 96 

Blue  vi  riol,  Hartz 98 

Crude  copperas,  Agordo 5 

Gneiss  at  Freiberg 79 

Lead  at  Mechernich 34 

Lead  from  desilverization  by  zinc, 

Mechernich 34 

Do.,     Commern 36 

Do.,     Call 38 

Lead,  1st  fusion,  Hartz 85 

Lead  pure,  Hartz 93 

Lead  precipitation,  Hartz 85 

Matte  at  Lend 46 

Matte,  copper,  Freiberg 72 

Matte,  cone.,  Freiberg 74 

Matte,  copper,  Hartz 94 

Ore,  Hartz 83 

Slag,  1st  fusion,  Lend 45 

Slag,  3J  fusion,  Lend 47 

SI  ;g,  ore  fusion,  Freiberg 66 

Slag,  matte  fusion,  Freiberg.  81  &  67 

Antimony,  removal  at  Call 37 

Antimony,  removal  by  poling 38 

Arsenical  ores,  treatment  of,   Frei 
berg 77  &  58 


Artificial  galena  from  roasting 30 

Augustins  muffle  furnace 74 

Bismuth,  extraction  of  at  Freiberg..  77 
Bismuth  in  desilverization  by  zinc. .  93 

Blowing  copper  at  Altenau 96 

Blue  vitriol,  Agordo 5 

Blue  vitriol,  Hartz 98 

Boeckstein  gold  ore 40 

Clausthal,  works  at 82 

Colorado  ores 52 

Condensation  of  Hg.  vapors. . .  21  &  25 

Copper,  loss  at  Agordo 11 

Copper  ore  at  Agordo 3 

Copper  process,  Freiberg 72 

Cost  of  copper  treatment,  Agordo  ..11 

Crystallization  at  Agordo 5 

Crystallization  at  Freiberg 7o 

Cupellation,  Freiberg 70 

Desilverization  at  Commeru 36 

Desilverization  in  Hartz .   90 

Desilverizatioti  at  Mechemich 33 

Dezincing  at  C  ill 37 

Dezincing  at  Mechernich 33 

FREIBERG 54 

Distribution  of  ores 54 

Yield  of  works 55 

Products 56 

Processes 56 

Classification  of  ores 53 

Preparatory  series  of  operations. .  57 

Gerstenhoefer  furnace 57 

Roasting 57 

Pyrites-  53 

Arsenical  ores 77  it  58 

Zinc  ores 5!) 

Pyritiferous  ores '  59 

Regular  series  of  operations 61 

Roasting  lead  ore 62 

Piltz  furnace 62  &  66 

Piltz  furnace  charge 65 

Charge  at  Halsbrucke 66 

Treatment  of  the  matte 07 

3d  and  4th  fusions 68 

Lead  treatment 68 

Refining 70 


via 


INDEX. 


Cupellation 

Second  appellation 

Copper  process 

Roasting  matte 

Crystallization 

Supplementary  Series 

Desilverization  of  abstrich  

Fusion  for  hard  lead 

Treatment  of  abstrich  scoria 

Manufac  ure  of  arsenic 

Extrao  ion  of  bismuth 

Review  oi'  j  >rocess 

Furnaces  inclined 

Gerstenhcefer  process 

Gold  in  Freiberg  ores 

Gold  ore  in  the  Tyrol 40— 

Gold  pao,  Austria 42— 

J'ashuer  furnace 

Hard  lead  prodaction,  Freiberg. . . . 

HARTZ  Mountains,  Lead  and  Silver 

Worts  of 

Works  at  Clausthal 

Composition  of  ore 

Proportion  of  products 

Charge,  1st  fusion 

Analyses  of  products 

Shalt  furnaces 

Kast  furnace 

Filtz  furnace 

Rachette  furnace 

Dvsiheriz.xtion  at  Lautenthal. . . . 

Deziucing  poor  lead 

Deziucing  rich  alloy 

Analysis  of  lead. . 


Copper  process  at  Altenau. 
.ble  of  copper  process. . . 


Ta 


Blowing  the  black  copper 

Solution  of  copper  ia  SOs 

Blue  vitriol 

Herbst  process  for  desilverization . . 

Idria 

Imbibition  in  Cupel  furnace 

Improvement  in  roasting 

— Addition  of  sulphuric  acid 

—  Precipitation  as  sulphide 

— Manufacture  of  iron 

Kast  furnace 87— 

Kernel  roasting  Agordo 

Kiln  roasting  Altenau 

Laut.  nthal,  works  at 

LEND,  Gold  and  Silver  Works  at. .  . 

Or  s  smelted  at 40  - 

Mill  process  

Austrian  pan  for  gold 

Pxiip 

Ex  r  Action 

Smeltiug 

First  fusion . . 


Second  fusion 46 

Fusion  with  lead 47 

Cupellation 47 

Tables  of  cost  and  yield 48 

Cost  for  various  ores 50 

Proportionate  yield  Au.  and  Ag. .  50 

Process  in  America 51  —  53 

Colorado  ores 52 

Liquation  of  rich  silver  alloy 33 

Lixiviation,  Agordo 5 

Matte,  concentration  of  Cu.  in 68 

Matte  '  reatmeut.  Freiberg 67 

Mercury  lost  in  panproce'S,  Austria  44 

MKCHEKNICH,  Lead  Works  at 29 

Year'y  product  of  mints 29 

Roasting 29 

Artificial  galena 30 

Fusion 31 

Furnace  dimensions ,  32 

Charge  in  smelting 32 

Desilverization 33 

Dezincing 33 

Analysis  of  lead 34 

Treatment  of  matte 34 

Works  at  Comnjern 35 

Desilverization,  Commern  .......  35 

Analys  s,  pure  lead 30 

Works  at  Call 36 

Zinc  charge 37 

Removal  of  antimony 37 

Mill  process  for  gold,  European. ...  41 

Muldner  Works,  yield  of 55 

Mines  of  Hartz,  yield,  1871 101 

Ores,  Classification  at  Freiberg 56 

Pan  process,  Austria 41 — 45 

Piltz  furnace,  Freiberg 62 

Piltz  furnace,  Hartz 89  -101 

Poling 35 

Precipitation  process  in  the  Haitz. .  8k! 
Precipitation  (Cu.),  improvement  in  15 

Preparatory  series,  Freiberg 57 

Products  of  mercury  distillation. ...  26 

Products  of  Freiberg  Works 56 

Proportionate  yield,  Au.  and  Ag.,  by 

fusion 50 

Pulp  used  in  p-n  process,  Austria.  .  44 

Pyritiferous  ores 57—59 

Rachette  furnace,  Hartz 85 

Rauris 40 

Review  of  Freiberg  process 78 

Ripa 27 

Roastii  g,  Agordo 4— 14 

Roas1  ing  at  Freiberg 67 

Roasting  lead  ore.  Freiberg .  62 

Roasting  matte,  Hnrtz 94 

Rousting,  Mechernich 3!>     35 

Silver,  separation  at  ("all 37 

Skofie,  cost  of  tre.itmcnt 15 


INDEX. 


Blag  in  charge,  Hartz 84 

{•unelting  gold  ores  at  Lend 45 

Soluble  sulphates  in  roasted  ore 13 

Turner,  Dr.  Leo 40 

United  States,  cost  of  Agordo  pro 
cess  in 19 

VAI.ALTA,  Mercury  Works  at 20 

Furnace 24 

Condensation 21—25 

Dimensions 22 

Condensation  chambers 21 

Tubes 24 

Loss 26 

Products 26 

Expense  of  tret\tment 27 

Compared  with  other  works 27 

Wot  treatment  for  rich  alloy 38 

Zell 40 

Zinc  charge,  M^chernich 33 

Do.,         Comrnem 86 

Do.,         Call 37 

Do,,        Lautonthal 90— 9i 


Zinc  ore«  at  Freiberg C9 

Zinc,  removal  of  at  Co rr.  morn 36 

Do.,  in  Hartz 91 

Do.,  at  Mecbcrnich. . . .  33 

Do.,  at  Call 37 

FIO.  FLLUSTnATIONS.  PAOE. 

1.  Ore  furnace,  Agordo 8 

2.  Blank  copper  furnace,  Agordo...    9 

3.  Mercury  furnace.  Valalta 23 

4  5.  D  ors  of  roasting  furnace  ...  30 

6.  Smelting  fort  noe,  Mecheruich..  31 

7.  Austrian  gold  mill 42 

8  -  9    lieverberatory  furnace,  Frei 
berg  60 

10.  Do.  Do 61 

11.  Piltz  furnace 6-4 

12—15.  Cupel  furnace.  Freiberg  ....  C9 

16— 1H.  K;ust  furnace,  Kurtz     86 

19-20.  li-iohetta  furnace,  Hartz-...  88 

21.  Do.  Do 89 

22.  .  Do.  Do..         ,.  80 


X*  XME 


THE  Notes  which  form  the  basis  of  the  few  papers  that  make  up  this  book 
were  taken  solely  for  private  use,  and  there  was  no  intention  of  making  them 
public  until  after  the  lapse  of  a  considerable  time.  Their  publication  was  then 
undertaken,  not  because  they  presented  descriptions  of  novel  processes,  but  be 
cause  the  author  found  that  the  poverty  of  English  technical  literature  in  this 
branch  of  industry  was  such  as  to  be  a  serious  annoyance  to  men  engaged  in  the 
treatment  of  American  ore«.  They  first  appeared  in  the  columns  of  the  Engi 
neering  and  Mining  Journal,  and  their  reception  has  been  sufficiently  favorable 
to  warrant  this  republication. 

It  is  frequently  said  that  American  genius  can  be  trusted  to  devise  its  own  pro 
cesses  and  need  not  go  abroad  for  instruction,  but  no  one  who  is  acquainted  with 
the  industry,  skill  and  devotion  of  European  metallurgists  to  thoir  work  can  be 
wiling  to  lose  the  fruits  of  their  experiment  and  thought.  Few  persons  know 
how  much  labor  and  money  are  spent  by  them  every  year  in  the  work  of  revising 
old  established  processes,  both  by  laboratory  examination  and  by  experiments 
conducted  on  the  largest  scale.  The  two  years  that  elapsed  between  the  author's 
journey  in  Europe  and  the  publication  of  these  Notes  was  sufficient  to  bring 
about  such  changes  and  improvements  in  foreign  practice  that  he  could  no 
longer  rely  upon  the  details  of  his  work  but  was  obliged  to  collate  it  with  the 
latest  technical  publications  abroad.  He  is  therefore  indebted  to  many  writers 
and  has  endeavored  to  properly  express  this  foot  in  foot  notes  to  each  paper. 
But  he  has  not  described  any  works  that  were  not  visited  and  carefully  stu 
died  by  him,  and  trusts  that  the  personal  knowledge  thus  gained  has  enabled 
him  to  appropriate  with  success  and  incorporate  with  his  own,  the  ^ork  of 
Others. 


NOTES 

ON  A 

METALLURGICAL  JOURNEY  IN  EUROPE. 


The  Copper  Process  atAgordo 

AOORDO  is  reached  from  Venice  by  rail  to  Conegliano,  stage  to  Belluno  and 
post-chaise  to  Agordo,  the  whole  journey  occupying  about  eighteen  hours.  The 
old  process  in  use  at  this  place  has  been  fully  described  by  KIVOT,  in  his  work 
on  Metallurgy  ;  by  HA.TON,  in  the  Annales  des  Mines,  1855,  5th  series,  vol.  8  ;  by 
PEKCY,  in  his  metallurgy,  and  many  other  writers.  It  will,  therefore,  receive  only 
such  attention  here  as  is  necessary  to  make  the  character  of  the  recent  changes  suffi 
ciently  clear. 

The  ore  is  obtained  from  an  irregular  deposit  of  iron  pyrites,  lying  in  black 
argillaceous  schist,  close  to  the  contact  plane  of  a  dolomite  limestone.  The 
dimensions  allotted  to  this  mass  by  Engineer  FELLAH,  are  : 

Length 550  meters. 

Breadth 35       " 

Depth 200      " 

Contents  in  cubic  meters 1,764,000 

He  reports  the  state  of  the  work  in  1865,  as  follows  :] 

Content  of  mass,  cubic  meters 1,764,000 

Already  excavated          "  , 617,000 

Worthless  pyrites'  "  441,000 

Good  ore  remaining      "  700,003 

As  the  weight  of  one  cubic  meter  of  pyrites  is  4,250  k.  (9,350  Ibs.)  we  have 
about  3,000,000,000  kilograms,  or  3,000,000  tons.  The  present  production  is 
about  20,000  tons  a  year,  at  which  rate  the  mine  will  hold  out  a  hundred  and  fifty 
years. 

About  one-third  of  the  ore  (see  above  statement)  is  worthless,  containing  no 
copper.  This  is  sorted  out,  and  the  remainder  is  separated  into  the  following 
varieties  : 

Best  ore. . .  .with  4  per  cent,  copper. 

Good  ore. .  .with  2—4  per  cent,  copper. 

Poor  ore with  0-4—2  per  cent,  copper. 

Small  ore.  ..with  1—2  per  cent  copper. 

1.  For  information  contained  in  these  notes  on  Agordo,  I  am  indebted  to  SIONOB  N. 
PELLVTI,  Eni<ineer  in  charge  for  the  .  talian  Government ;  and  to  SIONOB  LUIOI  HUB&BT. 
Director  of  the  Smelting  Works. 


This  small  ore  is  composed  of  a  mixture  of  all  the  other  varieties,  and  also  of 
ore  from  a  particular  layer  in  the  mine.  It  forms  somewhat  more  than  15  per 
cent  of  the  whole. 

Besides  the  pyrites  a  small  amount  of  galena  mixed  with  blende  and  contain 
ing  a  variable  percentage  of  silver,  is  obtained.  At  the  time  of  my  visit,  a 
gentleman  had  purchased  a  few  hundred  tons  of  this  ore  and  was  roasting  it  in 
piles,  in  the  hope  that  the  blende  would  roast  to  sulphate  and  thus  be  soluble, 
It  has  been  ascertained  that  when  a  mixture  of  lead,  zinc  and  silver  sulphides  are 
roasted  together  to  sulphates,  the  silver  is  not  soluble  in  the  presence  of  so  much 
lead.  His  roasting,  therefore,  had  for  its  object  the  removal  of  the  zinc  and  the 
concentration  of  the  silver  in  the  lead  ;  but  I  have  never  been  able  to  ascertain 
what  success  he  had,  though  I  am  under  the  impression  that  his  experiment 
foiled. 

In  treating  this  mass,  remarkable  for  its  purity,  methods  were  adopted  which 
made  Agordo  the  study  of  scientific  men.  The  ore  was  roasted  in  heaps  contain 
ing  250  to  300  tons,  the  temperature  being  kept  very  low,  and  after  six  to  nine 
months,  when  the  pile  was  opened,  a  kernel  of  unroasted  ore  was  found  in  each 
lump.  In  this  kernel  was  concentrated  most  of  the  copper  which  in  the  begin 
ning  had  been  distributed  throughout  the  lump.  A  transmission  of  solid  matter 
so  remarkable  as  this,  illustrating  the  operations  by  which  metallic  matter  may 
be  concentrated  in  veins  by  mundane  fires,  could  not  fail  to  attract  attention,  and 
nearly  all  writers  on  the  metallurgy  of  copper,  and  processes  of  roasting,  have 
discussed  it.2  These  kernels  were  broken  from  the  surrounding  "shells,"  and  in 
this  way  kernels  of  a  working  average  of  4 — 8  per  cent,  copper  were  obtained 
from  ore  containing  2  per  cent,  and  less  ;  while  the  shells  would  contain  about  0-7 
per  cent  The  concentration  of  copper  is  so  perfect  that  the  real  kernel  often 
contains  30  per  cent,  but  in  order  to  make  sure  that  none  of  the  rich  kernel  shall 
be  lost,  a  large  quantity  of  shell  is  left  around  it,  so  that  the  working  average  is 
that  above  given. 

Sulphur  is  collected  in  small  depressions,  stamped  in  the  top  of  the  pile.  Fine, 
sifted  ore,  from  the  lixiviation  vats,  is  stamped  into  circular  basins  and  a 
small  quantity  of  sulphur,  from  one-fifth  to  .one-half  of  one  per  cent  of  the  ores' 
weight,  collects  in  them.  This  is  refined  in  the  usual  way.  It  contains  arsenic 
and  is  not  a  very  valuable  product  In  1865  the  amount  made  was  50,532  k.  or 
60-5  tons.  This  is  0-3  per  cent,  of  the  ore  or  0'6  per  cent  of  the  sulphur  in  the 
ore. 

The  treament  of  the  two  sorts  was  :  Lixiviation  of  the  shells  with  precipita 
tion  of  the  copper  by  iron,  and  fusion  of  the  kernels. 

THE   WET   TREATMENT. 

Lixivialion.  The  ore  is  shovelled  into  vats  50  M  3-50  meters  square  and 
1  -50  meters  deep  ;  charge  14  tons.  Fresh  ore  is  lixiviated  with  liquor  which  hus 
already  served  for  two  lixiviations,  and  in  this  way  it  is  brought  up  to  the  proper 
strength.  The  liquor  remains  24  hours  in  contact  with  the  ore,  is  then  drawn 
off,  and  the  ore  shovelled  to  a  fresh  tank,  where  it  is  treated  with  water  from  a 

2.  See  I'lttttuur  a  Ko«jt  Pr«  zesee. 


AQORDO.  5 

previous  third  lixiviation.  After  24  hours  standing  the  pro  jess  is  repeated,  this 
time  with  fresh  water.  After  the  third  contact  with  the  ore,  the  liquor  marks  32° 
BE.VUME.  Liquor  from  the  second  lixiviation  marks  13°— 11°  B.  The  spent  ore 
is  placed  on  and  under  a  new  roasting  heap,  where  the  sulphurous  acid  fumes 
effect  a  re-roasting  of  it.  It  is  then  washed  in  4  waters,  sifted  through  a  mesh  of 
1-5  centimeters  =  0'6  inch,  and  the  coarse  ore  receives  a  third  treatment  in  the 
piles. 

Cementation .  The  liquor  from  the  lixiviation  vats  is  clarified  by  settling  in 
tanks,  and  then  run  to  the  cementation  vats.  These  are  of  two  kinds  :  lead  tanks 
4*3  nv-ters  and  1-5  meter  deep,  containing  21  cubic  meters.  They  are  heated 
by  a  lead  stove  placed  in  the  center,  and  the  flames  of  which  pass  downward 
through  a  large  flus  in  the  tank.  Fire  is  kept  up  for  8 — 10  houi's,  but  the  liquor 
remains  24  hours  in  the  tank.  Pig  iron  is  placed  in  a  bank  around  the  sides  of 
the  tank.  The  temperature  reaches  about  60°  G.  Reverbarat^ry  furnaces  are 
also  used  for  this  work.  They  have  a  bottom  laid  in  hydraulic  cement,  hold  17 
cubic  meters,  and  the  liquor  is  heated  by  the  flames  passing  over  it. 

Crystallization.  After  the  cementation  is  complete,  the  liquor  runs  to  clarifying 
vats  where  the  fine  copper,  and  the  basic  salts  in  suspension  in  the  liquor  settle 
to  the  bottom.  It  then  marks  about  37°  B.  and  is  transferred  to  the  crystalliza 
tion  vats,  which  are  wooden  tanks,  some  being  2-20  *  3-00  M  0.50  meters,  and 
others  8- 30  x  3-50  *  0-50  in  size.  Here  the  liquor  remains  as  long  as  it  is 
desired  to  continue  the  deposition  of  crystals.  Agordo  is  cold  in  winter  and  dry 
in  summer  ;  and  as  crystallization  practically  depends  partly  up ^n  evaporation 
but  mostly  upon  the  depression  of  the  temperature,  the  place  is  well  fitted  for 
the  manufacture  of  copperas.  By  leaving  the  liquor  in  the  vats  three  or  four 
months,  the  greater  part  of  the  iron  sulphate  could  be  obtained.  But  the  pro 
duction  of  Agordo  is  far  in  excess  of  the  demand,  so  that  there  is  no  neeed  to 
push  the  extraction  so  far.  Practically  the  liquor  remains  3—6  weeks  in  the 
vats.  The  crystals  of  sulphate  collect  on  the  bottom,  on  twigs  suspended  in  the 
liquor,  and  on  the  sides  of  the  tank,  and  these  conditions  afford  three  qualities  of 
copperas.  That  collected  on  the  bottom  is  the  poorest,  being  contaminated  with 
basic  iron  sulphate,  which  is  insoluble,  but  is  formed  in  such  a  fine  condition  as 
to  separate  completely  from  the  liquor  only  after  long  standing.  The  copperas 
on  the  twigs  has  a  certain  amount  ol  bark  and  woody  matter  in  it ;  that  on  the 
sides  is  pure  and  of  a  fine  color.  If  the  tanks  do  not  yield  enough  of  this  quality 
to  satisfy  the  demand,  the  mother  liquor,  after  the  first  crop  of  crystals  has  been 
obtained,  is  concentrated  in  the  revarberatory  furnaces.  It  then  yields  altogether 
first  quality  crystals.  In  the  ordinary  process  of  crystallization  the  strength  of 
the  liquor  sinks  from  37°  B.  to  26°  B. 

The  composition  of  this  sulphate  is  as  follows  : 

Ferric  sulphate 49-73 

Zinc  sulphate     . 4-55 

Hydratcd  Ferric  oxide 3-20 

Water..  ...42-52 


100 
The  amount  of  copperas  which  Agordo  is   capable  of  producing  each  year  is 


6  .AGORDO. 

immense.  If  we  assume  the  percentage  of  ferric  sulphate  in  the  liquor  to  increajse 
0-061  per  cent,  for  each  degree  of  BEAUME,  we  have  0  704  per  cent,  which  can  bo 
extracted  from  the  liquor,  by  lowering  its  density  from  37?  to  26°  B.  That  is, 
we  have  774  pounds  of  ferric  sulphate  from  each  cubic  meter  of  cement  liquor. 
RIVOT  says  that  each  cubic  meter  will  easily  give  600  k.  or  1320  pounds.  In  1865 
Agordo  produced  7360  cubic  meters  of  rich  liquor  and  1967  cubic  meters  of  poor 
liquor.  The  rich  alone  would  yield,  at  EIVOT'S  estimate,  4416  tons  of  copperas. 
But  the  production  for  the  year  is  reported  at  only  754  tons.  Agordo  is  so  far 
from  a  market  that  its  profit  on  this  product  is  very  small,  and  from  its  impure 
nature  the  demand  is  not  great.  •, 

The  operations  connected  with  mining  and  the  wet  treatment,  in  1865.  dealt 
with  the  following  quantities  of  material : 

TABLE   OP  OEE   MINED3. 

1.  Best  ore  containing  7*4  per  cent  copper    843  tons  containing  62  tons  copper. 

2.  Good      "  "3-1  per  cent  copper  5005     "  "        155     "  «« 

3.  Poor       "  "    0-87  per  cent  copper  10531     "  "          92     "  " 

4.  Small  j  Good  containing  2-48  p.  c.  copper  711     "  "          18     "          «• 
ore.      (Poor            •«        1-25  p.  c.      "      2261     "  28     " 

19,351  355 

Average  percentage  of  copper  1  -8 

TABLE   OF  BOASTING. 

The  Blasting  piles  received  bricks  and  fine  ore  for  covering 4,356  tons. 

coarse  ore 17,403  tons. 

Total 21,759  tons. 

Wood  consumed,  cubic  meters 201  -61 

"  "        cords  56-7 

Labor Roasting 2869  days 

Breaking  out  kernels .  39121  davs  41990  days. 

Per  ton  of  ore : Wood,  cords  0  '0029 

Labor,  days  :  roasting 0-132 

breaking 1  -800  1  -932 

Eesults: Kernels 2,324  tons  containing  copper  145-5  tons. 

Shells 17,607     "  "         "        209-5  tons. 

Rich  ore 475     "  ««        "         33*7  tons. 


Total  «  20,466  tons.  388-7  tons. 

TABLE   OF  LIXTVIATION. 

Shells  treated 17,667  tons  containing  copper 209-5  tons. 

Yield  :  Liquor 12,781  cubic  yards  containing  copper. . .  .116'3  tons. 

Loss 93-1  tons. 

Loss  calculated  on  copper  in  shells  is.  .  .44-5  per  cent. 
Loss         "  "         "     "   all  ores  is.  .23-8          «« 

Labor  1471  days  or  0'07d  per  ton. 

8.  This  table  is  computed  on  11  months  and  9  days  only. 

4.  The  difference  between  this  total  and  that  given  above  is  due  to  piles  which  were 
ot  fully  roasted. 


AOORDO.  7 

TABLE   OF   CEMENTATIOX. 

Charge  : Shells 17,667  tons  containing  copper 209-5  tons 

Product .    .    .  Rich  liquor 10,08G  cubic  yards. 

Poor      «•     2,695     " 

Cemeatcopper,  rich  188-7  tons    c(mtainjng  copper 

Loss 93-2  tons. 

Loss  therefore 44.5  p.  c. 

Fuel  : Peat (4-9  per  cent,  of  shells) 858  tons. 

Charcoal (=  0-023  per  cent,  of  shells) 691  bush. 

Iron 320-4  tons. 

These  amounts  give  the  following  as  the  expense  per  ton  of  shells  : 

Charge  : Shells 1  ton  containing  copper 23-70  pounds. 

Rich  liquor 0-57  cubic  yards. 

Poor     "      0-16      "         " 

Cenvnt  copper. .  .0.135  tons  containing  copper 13-16  pounds. 

Loss (=  44-5  per  cent. ) , 10-54         » 

Fuel : Peat 97  ponnog  (=  4-9  per  cent.) 

Charcoal 0-039  bushels. 

Iron: 36-23  pounds. 

The  expense  per  ton  of  pig  copper  produced  is  as  follows 

Charge  : Shells 1519  tons  containing  copper 3602  pounds. 

Cement  copper..  ..  2382  pounds    "  "        2000 


Loss (44-5  percent) 1602         " 

Fuel  : Peat 14,780  poun-ls. 

Charcoal ....  6  bushels. 

Iron 5,510  pounds. 

THE   TREATMENT  BY   FUSION. 

The  process  consists  in  fusing  the  kernels,  rich  ore  and  cement  copper  with 
sandstone  as  a  flux  ;  the  rich  scoria  obtained  in  this  and  succeeding  operations 
being  added  for  the  sake  of  their  copper.  The  furnace  employed  is  very  peculiar, 
the  back  and  front  walls  being  strongly  inclined  to  the  horizon.  The  furnace  is, 
therefore,  in  effect,  an  ordinary  shaft,  tilted  over  about  12  degrees  from  the 
perpendicular.  The  object  of  building  it  in  this  way  is  to  make  the  ore  pass  slowly 
through  the  furnace,  the  inclination  of  the  back  wall  increasing  the  friction  ;  and 
also  to  oblige  the  gases  to  follow  the  front  wall  and  mix  with  the  ore  as  little  as 
possible  in  order  to  avoid  too  great  reducing  action.  These  dispositions  have 
for  their  object  the  prevention  of  iron  sows,  and  the  proper  preparation  of  the 
materials,  during  their  descent,  for  fusion  in  the  crucible.  It  is  hardly  worth 
while  to  discuss  forms  so  peculiar,  and  so  little  likely  at  this  day,  to  meet  with 
copyists.  But  similar  constructions  have,  in  times  past,  been  common  in  Europe, 
as  in  the  Hartz.  They  have  now  been  abandoned  in  most  quarters,  but  it  may 
be  well  to  point  out  that,  with  ore*  rich  in  iron,  sows  can  be  better  prevented  by 
a  rapid  smelting,  than  by  any  other  means  ;  and  if  this  rapid  fusion  does  not 
permit  the  necessary  preparation  of  the  materials  in  the  furnace,  they  can  be 
prepared  before  they  enter  it.  This  preparation  in  the  furnace  consists,  accord- 


8 


AGOKDO. 


ing  to  the  Agordc  view,  partly  in  driving  off  the  sulphur,  and  partly  in  heating  the 
materials.  But  sulphur  can  be  eliminated  to  but  a  very  small  extent  in  the 
shaft  furnace.  Raw  ores,  such  as  the  greater  part  of  those  smelted  at  Agordo, 
practically  are,  can  hardly  lose  more  than  4  per  cent,  of  their  sulphur  in  passing 
through  the  furnace,  a  quantity  which  could  be  eliminated  by  roasting  one- 
twentieth  part  of  the  ores  before  charging.  With  the  Agrordo  system  of  building 
is  connected  the  very  serious  defect  of  short  campaigns.  Eighteen  days  was  the 
average  of  the  furnaces  in  1865.  By  roasting  (if  necessary)  a  part  of  the  ores 
and  smelting  12—15  tons  daily  instead  of  9,  and  using  a  straight  or  a  flaring 
urnace,  the  campaigns  might  be  trebled  in  length,  and  the  cost  of  working 
reduced. 


Figure  /. 

Figure  1  represents  a  section,  from  front  to  back,  of  the  furnace  used  for  the 
fusior  of  ore. 

By  reference  to  the  tables  further  on  it  will  be  seen  that  the  expense  of  fuel  per 
ton  of  charge  is,  in  the  fusion  of  ore,  about  25  bushels  per  ton,  and  in  that  of 
matte  37  bushels  ;  the  former  being  15  and  the  latter  more  than  22  per  cent,  of 


AGORDO. 


the  charge.  This  expense  would  probably  be  considerably  reduced  by  the  adop 
tion  of  furnaces  less  wasteful  of  fuel  and  capable  of  maintaining  longer  cam- 
pudgns.  Even  at  Lend  where  the  campaigns,  for  lack  of  ore,  are  confined  to  a 
week's  run,  or  less,  the  expense  of  fuel  is  i  o  greater. 

The  resulting  matte  contains  about  24  per  cent  of  copper.  It  is  roasted  in 
piles  six  times  and  smelted  with  sandstone  and  rich  scoria.  The  furnace  is 
again  inclined,  but  less  so  than  before,  as  figure  2  shows.  It  is  important,  in 
this  operation,  to  prevent  the  reduction  of  too  much  iron  which  would  make  a 
highly  ferriferous  black  copper.  The  siliceous  flux  used  at  Agordo  costs  $1.36 
a  ton,  and  as  it  coutains  about  10  per  cent  of  iron  the  amount  must  be  increased 
over  that  which  would  be  necessary  if  the  quartz  were  purer.  It  is,  therefore,  an 
object  to  smelt  with  a  charge  as  basic  as  possible,  a  treatment  which  increases  the 
danger  of  redui-ed  iron. 

From  this  operation  black  copper  of  95  per  ceni,  copper  and  a  richer  matte, 
containing  about  60  per  cent  copper,  are  obtained.  The  former  is  fined  in  a 
common  German  hearth,  and  the  latter  is  roasted  and  returned  to  the  same 
operation. 


TAJV-ES   OF   THE   TREATMENT   BY  FUSION. — FUSION    FOB   MATTE. 


Charge 


Kernels            Best      8  -67 

"-  :;;25i 

Good    6-39 

.1752 

Poor     3  -37 

287 

Rich  cement  copper  58  -57 
Poor         "            "     9  "89 

18S 
26 

Grasses  &  Cinders     34  '50 

106 

546 

Sandstone.  . 

679 

4182  tons. 


10 


AGORDO. 


Product : Matte  containing  23 -'25  per  cent,  copper 1285-0  tons. 

Grasses         *•        10  ««  "     J4-9     " 

Cinders        "        15  "  "  11-3     " 


Labor  : 16  campaigns,  or  843  shifts  of  8  hours  each  ; 

4  men    o  each  shif 

Fuel : Charcoal  4735  cubic  me'  ers 

Charge  smelted  in  24  hours 

Lab'  »r per  ton  of  charge 

Fuel f     "         "         

Loss  : The  char  -e  con'ained  of  copper 

The  produc  s         "  "         


1311-2  :ons. 


days. 
106,310  bushels. 
14-8  tons. 
0-8  days. 
25-4  bushels. 
64  s,  083  pounds. 
603,742 


Loss  therefore        "  '«         38,346        " 

Or 5-9  per  cent. 

BOASTING   OP    MATTE. 

Matte 1488  tons per  ton. 

Charcoal 18288  bushels 12-3  bushels. 

Wood 251  cords 0-15  cords. 

Peat 55-4  tons 0-03  tons. 

Labor 5040  days 3 '15  days. 

FUSION   FOR   BLACK   COPPER. 

Charge  : Boasted  matte  containing  23-2  per  cent,  copper 1343  tons. 

60.8     "       "         "      175    " 

Grasses  and  cinders 25    " 

Scoria 380    " 

Sandstone.  .* 477    " 

2400 

Products  :. .  .Matte  containing 60-26  per  cent  copper. .,  .191-6  tons. 

Black  copper  containing 90          "       "         "     ....314-4    " 

Crasse 15 '        "       "         "     20-3    " 

Cinder* 10          "       "        «     ....12-8    " 

539-1 

Labor  : 747  shifts,  4  men  to  each  shift 2988  days. 

Fuel : Charcoal 88,047  bushels, 

Labor  : per  ton  of  charge I" 24  days. 

Charcoal  :'.'..'*«       "         "         37       bushels. 

Charge  smelted  in  24  hours . 9-5  tons. 

Loss  : The  ciiarge  contained  of  copper 869,41 1  pounds. 

The  products         "  "        837,016 

Loss  therefore 32,395  pounds. 

Or •        3-7  percent 

FINING. 

Charge  : Black  copper 628,443  pounds. 

Product  :.... Rosette     "      492,840 

Grasses  and  cinders 96,228 

Labor  : 1,296  days. 

Fuel : Charcoal 24,000  bushels. 

Copper  in  materials  charged 597,025  pounds. 

obtained 589,068 

Loss  therefore 7,957 

Or 1-33  per  cent 


AGORDO. 


11 


TABLE   OF   LOSS. 

Copper  In  charge.          C  .ppor  In  products.  LOBB.     Per  Cent 

Lixiviation  ............  4  IS,  895  pounds.         232,  600  pounds.  186,  289        44  -5 

Firstfusioii  ...........  641,641       "                603,742       ••  37,899           V.l 

Second  fusion  .........  860,400       "                837,016       »  32,384          3-7 

Fining  ...............  597,025       "                589,068       "  7,957        1  -33 

2,526,961  2,262,432  264,529  f 

This  amounts  to  a  loss  of  34-42  per  cent  of  the  copper  in  the  ores.  But  this  is 
too  high,  because  all  the  products  from  the  piles  and  the  cementation  vats  were 
not  smelted  within  the  year.  Knowing  the  percentage  of  loss  on  each  operation 
we  can  calculate  the  true  loss  on  20,466  tons  of  ore  containing  388-7  tons  copper 
as  follows  : 

Lixiviation  loss  on  ____  418,800  Ibs.  copper  0  44-5  per  cent.   =  186.366  pounds. 
____  590,834"         ••        @    5-9"         "     =     34,859 


Firstfusioii 

Second  fusion  loss  on.  555,  975 

Fining  "     "    535,404 


=     20,571 

=       7,139 


the 


Total 777,400  Ibs.  32  -0  per  cent.  248,935  It* 

Engineer  PELLATI  reports  the  loss  for  1865  at  31  -8  per  cent. 

From  this  it  appears   that  roasting  and   its  accompanying   lixiviation  are 

processes  which  cause  the  greatest  loss,  and  are,  therefore,  the  least  perfect. 
Expense  per  ton.  To  ascertain  the  average  cost  of  one  ton  of  pyrites,  we  will  take 

the  following  amounts;  best  ore  406,547k.,  kernels  2,081,447,  shells  16,060,785 

k.  ;  total  18,548,779  kilos  or  20,399  tons.     The  expenses  of  labor  and  material 

upon  each  ton  of  this,  in  all  the  operations,  is  as  follows  : 

TABLE   OF   EXPENSE   FOR    2000    POUNDS    ORE,  IN   UNITS    OF   LABOR    AND    MATERIAL. 


Labor 
days. 

Wood 
Cords. 

Char- 
coal 
bushels. 

Peat 
tons. 

Iron 
pounds. 

Sand 
stone 
t»ns 

1-93 

0  003 

Ijixiviation 

0-07 

Cementation 

0-12 

.    .. 

0-034 

0-042 

31-41 

Fusion  for  matte 

0-17 

5-160 

0-028 

0  25 

0  012 

0.9  JO 

0-002 

0-15 

4-310 

0-023 

Fining 

0-06 

1-18 



2-75 

0-015 

11,584 

0-044 

31-41 

0-051 

Prices  at  Agordo  are  as  follows  : 
Mining  ore 9-55  francs  per  ton 


=  $1-91 


per  cubic  meter  =          8-5  cents  per  bushel.          j 
"         •'         "    =  $2-13  per  cord. 
««         •«          "     =$15-00  per  ton. 
1000  k.      =$27-26  per  ton. 
"  day  (average)  =         20  cents  a  day. 
1000k.      =  $1-36  a  ton. 


Otiarooal 12-25 

Wood 3-00 

Peat 3-00 

Iron 15U-00 

Labor 1-00 

Sandstone 7- 50 

From  the  above  table  of  loss  it  is  apparent  that  the  old  process  in  use  at  these 
works  was  a  very  expensive  one,  considered  in  regard  to  extraction.  The  loss  in 
lixiviation  was  enormous,  and  improvement  in  that  part  of  the  process  would 
evidently  afford  the  beat  reward.  But  this  truth  was  not  immediately  perceived  ; 


12  AGORDO. 

a  number  of  minor  matters  first  received  attention,  and  the  changes  introduced 
were  not  always  useful. 

Improvement  at  Agordo  first  took  the  direction  of  attempts  to  increase  the 
amount  of  sulphur  extracted  ;  and  to  concentrate  the  copper  more  perfectly  in 
the  kernel.  Although  the  ore  contains  50  per  cent.,  or  more,  of  sulphur,  the 
piles  save  at  most  one  half  per  cent.  To  increase  the  yield  the  "  Styrian  Kiln" 
was  adopted.  This  is  merely  a  rectangle,  enclosed  by  walls  and  paved  with  stone. 
In  the  walls,  which  are  very  thick,  there  are  a  number  of  chambers,  communica 
ting  with  the  interior,  by  small  passages.  The  ore  is  filled  in  and  covered  with 
fine  ore,  and  fine  spent  ore  from  the  lixiviation  vats  is  stamped  on  the  top  for  a 
cover.  The  ore  is  ignited  by  a  canal  in  the  bottom  of  the  kiln,  and  the  roasting 
goes  on  precisely  as  in  a  pile  ;  but  the  products  of  combustion  are  discharged 
through  the  side  passages.  As  the  sulphur  vapors  are  longer  in  passing  out,  and 
the  masonry  in  which  they  circulate  is  exposed  to  the  air,  they  are  more  thoroughly 
cooled  and  condensed,  Al  the  same  time  the  thick  walls  serve  to  retain  the  heat 
of  the  mass,  which  reaches  a  temparature  probably  considerably  higher  than 
that  of  the  pile.  The  result  of  these  conditions  is,  that  nearly  one-half  more 
Bulphur  is  condensed,  and  the  higher  heat  produces  better  kernels.  Indeed,  poor 
ore,  that  gives  no  kernels,  when  roasted  in  piles,  yields  them  in  the  kilns.  The 
experiment  was  therefore  a  success,  in  having  fulfilled  the  expectations  formed  of 
it.  But  this  was  the  turning  point  in  Agordo  improvement.  The  high  beat 
which  made  the  kernels  so  fine,  also  caused  the  destruction  of  the  copper  sul 
phate,  in  the  shells  ;  the  sulphuric  acid  was  driven  off,  and  copper  oxide  left. 
This  is  insoluble  in  water,  and  caused  a  great  increase  of  the  loss  in  the  process 
of  lixiviation,  a  loss  which,  as  we  have  already  seen,  reached  44-5  per  cent  of  the 
copper  treated.  The  sulphur  at  Agordo  is  always  contaminated  with  arsenic,  and 
its  use  is  restricted.  Its  price  is  therefore  low,  and  its  production  unimportant. 
These  considerations  led  at  once  to  the  disuse  of  the  Styrian  kiln,  (s)  and  im 
provement  took  its  true  direction  in  efforts  to  increase  the  yield  of  copper  and 
lessen  the  expense  of  operations  subsequent  to  the  roasting.  Great  results  have 
been  attained  in  this  work.  They  are— 1st.  The  almost  complete  extraction  of 
the  copper  by  roasting  and  lixiviation  ;  2d.  Projected  improvements  in  cementa 
tion,  which  include  the  disuse  of  all  operations  but  Roasting,  Lixiviation,  Fining 
and  Crystalization. 

Improvements  in  Roasting — One  of  the  peculiarities  of  the  Agordo  deposit  is  a 
layer  of  hygroscopic  pyrites,  which  falls  to  pieces  up<-n  contact  with  the  air. 
This  is  mnde  into  round,  conical  bricks,  which  are  dried  and  then  piled  like  the 
other  ore.  But  to  save  the  expense  of  ovens,  which  are  necessary  in  the  winter, 
the  extraction  of  this  ore  has  been  confined  to  the  summer  season.  It  is  now 
proposed  to  build  crushing  works,  and  break  up  all  the  ore,  except  the  richest,  to 
the  size  of  one  centimeter  (O4  inch).  It  will  then  be  stamped  into  bricks.  These 
have  the  shape  of  a  truncated  cone,  with  a  height  of  10  centime'ers  (-1  inches), 
and  a  mean  diameter  of  15  centimeters  (6  inches.)  Three  moulds  are  cast  in  one 

5.  One  of  these  kilns  is  still  in  use,  but  only  for  want  of  room  for  the  roasting 
piles. 


AGORDO.  13 

piece,  and  a  workman  can  make  600  bricks  by  four  o'clock  p.  M.,  his  work  being 
as  follows  :  bringing  and  wetting  his  ore  with  mother  liquor  from  the  crystaliy-iv- 
tioii  vats  ;  forming  the  bricks,  and  carrying  them  to  the  drying  ground.  It  should 
be  remarked  in  regard  to  the  time,  thut  the  workmen  at  Agordo  are  compelled  to 
leave  work  at  4  p.  M.  ,  because  of  the  sulphurous  acid  vapors  from  the  rousting 
piles,  near  which  they  work,  'ihere  is  nothing  in  the  work  itself  which  forbidx  a 
full  day's  labor,  and  a  production  of  at  least  one-sixth  more.  The  bricks  weigh 
about  2  k.  or  4-5  pounds  each.  They  are  air  dried,  and  then  uiled  on  the  outwide 
of  roasting  piles  in  full  operation,  and  completely  dried.  The  weak  solution  of 
iron  and  zinc  sulphates,  which  forms  the  spent  liquor  from  the  crystalization  vatn, 
acts  with  a  slight  oxidizing  effect  upon  the  grains  of  pyrites,  and  binds  them 
together  like  a  cement  ;  the  bricks  are  consequently  quite  hard. 

After  drying  they  are  piled  in  regular  order,  70,000  or  80, 000  in  a  pile  ;  covered 
with  small  ore,  and  lighted  as  usual  with  logs  of  wood  placed  at  the  cornerw. 
When  fully  ignited  a.  layer  of  spent  roasted  ore  from  the  lixiviation  vats  is  thrown 
over  the  pile  to  serve  as  a  cover.  The  roasting  period  is,  as  usual,  7 — 9  months, 
according  to  the  size  of  the  pile.  This  is  then  opened,  and  each  brick  is  broken 
in  two  to  ascertain  whether  it  is  fully  roasted.  Those  which  are  underburueU 
are  thrown  into  a  pile  of  fresh  bricks  and  reroasted.  It  is  the  peculiarity  of  thiw 
method  that  no  brick  is  ever  ouer-roasted,  a  fact  that  is  full}'  proved  by  fifteen 
years'  uniform  experience, 

A  perfect  roasting,  for  purposes  of  lixiviation  with  water,  is  that  which  leaved 
the  greatest  possible  amount  of  sulphates.     How  much  superior  this  roasting  of 
the  ore  in  brick  form  is  over  that  in  lumps,  is  shown  by  the  following  resulta  com 
municated  by  Signer  de  HUBEET  : 
Fine  ore,  stamped  in  moulds,  roasts  to  a  red-brown  color 

and  loses  in  lixiviation 30  @  32  per  cent 

Ore  in  lumps,  well  roasted,  but  of  a  darker  color,  loses 18  @  25     "       " 

The  same,  over-roasted,  nearly  black  in  color,  loses 14     "      " 

Thus  we  see  that  the  gain  by  crushing  and  moulding  the  ore  is  twofold.  Over 
roasting  is  steadily  avoided,  and  the  roasting  is  better  than  the  best  in  any  other 
form. 

This  gain  in  soluble  matter  is  of  course  principally  iron  sulphate,  but  it  is  a 
well-known  fact  that  copper  sulphate  is  much  less  easily  decomposed  by  heat  than 
iron  sulphate,  and  we  ought  therefore  to  expect  an  increase  in  the  proportionate 
extraction  of  copper  even  greater  than  that  of  the  iron  salt.  If  we  take  the  ave 
rage  extraction  of  iron  sulphate,  from  the  lump  ore,  to  be  22  per  cent.,  and  from 
the  brick  ore  31  per  cent,  the  latter  gives  about  33  per  cent,  greater  yield  of  this 
salt  than  the  former.  We  have  seen  that  the  loss  of  copper  in  roasting  and  lix 
iviation  is  estimated  at  no  less  than  44*5  per  cent,  while  experiments  on  the  new 
method  indicate  a  loss  of  only  3  or  5  per  cent,  which  is  a  gain  in  extraction  of 
75  per  cent  These  results  are  astonishing,  and,  simple  as  the  means  taken  to  pro 
duce  them  are,  must  be  underlaid  by  some  general  principles  of  value. 

Were  the  molecules  of  which  each  lump  of  ore  is  composed  independent  of  each 
other,  we  should  probably  have  an  almost  complete  conversion  of  the  sulphido 
into  sulphate  in  roasting,  as  the  heat  produced  by  the  combustion  of  one  extra 


14  AGORDO. 

atom  of  sulphur  does  not  seem  sufficient  to  destroy  the  sulphate  salt  formed  by  the 
burning  of  the  other.  When  this  destruction  does  take  place,  it  is  probably  due 
to  the  fact  that  the  particles  of  ore  do  not  all  reach  the  sulphate  stage  at  the  same 
moment,  and  those  that  arrive  there  first  are  subjected  not  only  to  the  effects  of 
the  heat  stored  up  in  them  by  the  combustion  of  their  sulphur,  but  also  to  the 
added  heat  which  the  neighboring  particles  of  sulphide  give  out  in  burning. 
Among  the  remedies,  which  have  been  proposed  for  this  evil,  is  the  admixture  of 
inert  substances  to  keep  the  particles  of  roasting  matter  apart.  The  improvement 
at  Agordo  may  properly  be  placed  in  this  class,  though  the  substance  mixed  in 
with  the  ore  is  not  a  solid,  but  a  gas  ;  it  is  air.  But  the  air  performs  the  func 
tions  of  an  inert  non-conductor,  and  it  is  to  this  property  that  it  owes  its  value. 

The  reason  why  the  bricks  roast  better  than  the  lumps  is  doubtless  to  be  found 
in  the  difference  in  the  physical  condition  of  the  ore,  produced  by  crushing,  or  by 
the  natural  disintegration  of  the  hygroscopic  ore.  The  superiority  of  the  small 
ore  is  in  the  severance  of  the  mathematical  contact  naturally  existing  between  ore 
particles,  in  large  lumps.  That  it  plays  an  important  part  is  proved  by  the  fact, 
that  no  kernels  are  ever  found  in  the  bricks  formed  of  small  ore,  the  concentra 
tion  of  copper  in  the  centre  being  prevented  by  the  separation  of  the  lump  into 
an  infinite  number  of  small  grains,  which  have  no  perfect  contact.  In  the  kernel 
roasting,  for  which  this  place  has  been  so  famous,  it  has  been  observed  that  the 
copper  in  one  lump  has  sometimes  been  concentrated  in  a  neighboring  lump, 
lower  in  the  pile,  with  which  it  came  in  contact.  For  the  transmission  of  copper 
from  one  lump  to  another  by  any  process  yet  suggested,  an  absolutely  mathema 
tical  contact  is  indispeusable.  Whatever  the  true  method  ot  that  transmission 
may  be,  it  is  evident  that  an  action,  so  exceedingly  slow  and  delicate  as  it  must 
be,  could  not  proceed  if  the  least  chasm  or  other  obstruction  lay  in  the  way  of  the 
advancing  copper.  There  must  Lave  been  a  mathematical  contact  between  the 
two  lumps  ot  ore,  and  it  remains  to  explain  why  two  neighboring  grains  in  a  brick 
cannot  come  into  equally  intimate  union. 

The  explanation  given  at  Agordo  for  the  transfer  of  copper  from  one  ore  mass 
to  another,  is  that,  in  a  pile  made  up  of  irregular  lumps,  there  will  be  irregularity 
of  interstices  also,  and  some  of  the  open  spaces  will  be  so  large  as  to  furnish  air 
enough  to  cause  too  rapid  combustion  in  the  pieces  immediately  around  them. 
The  heat  being  thus  raised,  the  mass  of  pyrites  melts  superficially,  and  flows 
down  upon  the  lump  below,  thus  establishing  the  close  contact  necessary  for  the 
transmission  of  the  copper,  in  its  process  of  concentration. 

In  the  brick  made  up  of  grains,  none  of  which  are  larger  than  1-16  cubic  inch 
and  most  are  from  1-4  to  1-10  inch  iu  diameter,  this  rapid  fusion  cannot  proceed. 
Even  if  one  particle  gets  into  furious  combustion,  the  air  which  almost  surrounds 
it  prevents  the  transmission  of  its  heat  and  there  is  no  general  fusion  of  the  sur 
face  of  the  brick.  Thus  the  air  maintains  the  disaggregation  of  the  pile. 

Admixture  of  an  inert  solid,  like  silica  or  shale,  serves  the  same  purpose  as  air. 
The  poor  ore  at  Agordo  rarely  has  kernels,  or  only  inferior  ones.  The  interposi 
tion  of  the  silica  prevents  the  advance  ol  the  copper ;  and  when  kernels  are 
formed  it  cannot  be  doubted  that  the  gangue,  always  small  in  quantity,  is  absent, 
or  nearly  so,  from  those  pieces  which  give  the  kernel.  Thus  we  may  refer  the 


AGOBDO.  15 

slow  and  even  roasting  of  the  bricks  to  the  separation  of  the  ore  particles  which  in 
accomplished  by  crushing  ;  while  the  maintenance  of  this  separation  is  due  to  the 
non-conductor—air — by  which  they  are  nearly  surrounded,  - 

These  facts  may  be  observed  daily  at  Agordo.  The  piles  made  up  ore  brick* 
are  much  less  aggregated  by  fusion  than  the  others.  Ordinary  piles  are  found  to 
consist,  after  burning,  of  a  mass  which  has  gained  decided  coherence  by  the  heat 
it  has  undergone.  The  ore  must  be  knocked  out  by  strong  blows  of  a  hammer  ; 
while  the  bricks,  though  somewhat  coherent,  yield  much  more  readily. 

It  is  proposed  to  take  advantage  of  these  results  of  many  years  experience  and 
erect  (1)  Crushing  works  in  which  whatever  crusher  is  selected  will  have  to  exert 
both  a  crushing  and  a  percussive  action,  as  the  Agordo  ore  is  very  hard  aud 
tongh  ;  (2)  Ovens  for  drying  the  ore.  (The  order  for  these  had  been  received  in 
1869  )  In  addition  to  this,  there  will  probably  be  some  changes  in  manipulation, 
as  at  the  lixiviation  tanks  where  the  ore  is  now  moved  twice,  instead  of  pumping 
the  liquor,  a  much  less  laborious  operation  ;  but  of  this  kind  of  improvement 
which  is  merely  the  reforming  of  a  bad  disposition  of  the  works,  and  includes  no 
principle,  I  do  not  intend  to  speak. 

The  next  field  in  which  improvement  ia  to  enter  is  the  precipitation  of  the 
copper  by  iron.  Three  propositions  are  now  before  the  government,  as  follows  . 
1.  Hot  precipitation  in  revolving  casks,  12  feet  in  diameter,  as  at  Skofie  in  Austria. 
This  operation  is  thus  shortened  to  12  hours,  no  basic  salts  are  produced,  little 
arsenical  salt  precipitated  and  the  amount  of  iron  used  is  practically  a  minimum  ; 
90  iron  to  100  cement  copper  or  154  iron  to  100  pig  copper.  It  is  difficult  to 
institute  a  fair  comparison  between  the  Skofie  method  and  that  at  Agordo,  though 
the  ores  have  about  the  same  value,  because  the  ore  of  the  former  is  already  an 
oxide  ;  but  leaving  out  the  roasting  in  both  cases,  the  following  comparison  of 
loss  and  expense  of  material,  in  other  operations,  gives  a  good  idea  of  the  decided 
differences  in  the  two  systems. 

To  produce  1000  k.  (2200  pounds)  rosette  copper,  requires  at 

Agordo.  Skofie. 

Copper  in  the  ore 1412  kilos.  1202  kilos. 

Wood 1-90  cubic  metenu 

Peat 19-10     " 

Charcoal 34-40     "  "                                 61m. 

Iron 2750-00  kilos.  1540  kilos. 

Sandstone 4460-00     "  1540     " 

This  comparison  is  the  more  striking  when  we  remember  the  fact  that  only  46  per 
cent,  of  the  copper  which  was  smelted  at  Agordo  had  passed  through  cementation. 
The  rest  was  obtained  from  kernels  and  rich  ores. 

2.  Addition  of  sulphuric  acid  to  the  liquor  during  cementation.  This  is  the 
suggestion  of  Signer  DE  HUBEBT,  director  of  the  smelting  works,  who  has  worked 
out  the  method.  The  greatest  defect  of  the  present  system  of  precipitation  is  the 
production  of  basic  salts  of  iron.  These  are  the  result  of  the  long  contact  of  the 
hot  liquor  with  the  pig  iron  in  the  tanks  and  they  cause  a  loss  of  iron,  a  precipi 
tation  of  arsenical  salts,  and  by  adulterating  the  cement  obtained,  they  prevent 
the  immediate  conversion  of  the  cement  to  pig  copper,  and  thus  cause  a  loss  of  9 
per  cent  of  the  copper  in  the  cement,  by  the  double  fusion  which  is  necessary. 


16  .AGORDO. 

Signer  DE  HUBERT  finds  that  these  inconveniences  can  be  avoided  by  the  addition 
of  sulphuric  acid  to  the  cement  liquor,  a  course  which  carries  with  it  only  two  ob 
jections  ;  the  cost  of  the  acid  and  the  use  of  more  iron  ;  while  its  advantages  are 
the  production  of  a  cement  which  can  be  smelted  at  one  operation  to  fine  copper  ; 
and  a  larger  make  of  copperas.  The  latter,  it  is  true,  arises  partly  from  the  sul 
phuric  acid  added  and  the  extra  amount  of  iron  consumed  ;  but  also,  Irom  the 
prevention  of  the  basic  salts. 

Experiments  in  the  laboratory  gave  the  following  results  : 
.  Without  sulphuric  acid,  the  cement  contained  1 — 3  percent,  of  arsenic  and  30  per 

cent,  of  copper,  the  impurity  being  chiefly  basic  iron  sulphate. 
With  sulphuric  acid  the  cement  contained  no  arsenic,  no  basic  salt,  and  67—73 
per  cent,  of  copper  ;  the  impurities  being  carbon  from  the  iron,  iron 
powder,  ore  particles  and  sulphur.     The  latter  was  in  so  small  quantity 
that  the  cement  was  well  adapted  for  immediate  fining. 
An  experiment  in  the  large  way  resulted  as  follows  : 

Amount  of  cement  liquor  (charge  for  one  vat)  16-75  cubic  meters. 
Concentrated  acid  1  -25  litres  (4  Ibs. ) 
Iron  consumed  to  100  copper  232  -00 
Cement  contained  copper  75-3  per  cent. 
Arsenic  none. 

The  importance  of.  avoiding  the  formation  of  basic  salts  Is  seen  from  the  fact 
that  of  the  cement  obtained  in  1865  : 

375,800  pounds  contained  only  58 '57  per  cent,  copper  =  220,106 
51,790        «  "  "      9-89     "      »        "       =      5,122 

Total  copper ppunds 225,228 

Allowing  33  per  cent,  for  impurities  by  the  proposed  method  (see  experiment  in 
the  large  way)  the  production  of  cement  to  yield  this  amount  of  copper  would  be 
297,007  pounds.  As  the  amount  by  the  old  method  was  427,590  pounds,  we  may 
look  upon  the  difference,  or  130,533  pounds,  as  the  amount  of  the  basic  salts. 
These  salts  have  the  following  composition  : 

Sulphuric  acid 35  35 

Ferric  oxide .43-21  Iron  30-24. 

Alumina 15-71 

Zinc  oxide 5-53 

96-80 

In  addition  to  this  they  contain  a  variable  quantity  of  water. 

The  enormous  consumption  of  iron,  two  and  three  quarter  pounds,  for  every 
pound  of  copper  precipitated,  in  1865,  is,  therefore,  partly  due  to  the  formation 
of  these  insoluble  salts  ;  for  they  are  formed  by  the  union  of  a  certain  quantity  of 
the  soluble  sulphates  with  the  iron  introduced  into  the  vat.  But  the  amount  of 
iron  thus  taken  up  is  only  a  little  less  than  22  parts  for  every  100  of  basic  salt,  01 
about  29, 000  pounds  of  iron  thus  wasted  in  that  year.  This  does  not  by  any 
means  account  for  the  quantity  of  iron  nsed.  But  an  analysis  of  the  liquor  ob 
tained  from  Agordo  ore,  shows  that  it  contained  an  average  of  one-hall'  per  cent. 


AGOflDO.  17 

of  sulphuric  acid.     AB  there  wer«  345,087  cubic  feet  of  liquor,  the  amount  of  free 
acid  was  108,340  pounds.     The  statement  for  1865  would  therefore  be  as  follows: 

Necessary  -to  precipitate  the  copper 195,610  pounds  iron. 

Taken  up  by  basic  salts 28,601  " 

44    free  sulphuric  acid 72,226 

296,437 
Amount  of  iron  used ". 640,800 

Amount  not  accounted  for 344,363 

Thus  we  are  unable  to  trace  more  than  half  of  the  iron  which  is  consumed.  If 
we  allow  6  per  cent  for  carbon  and  other  impurities  in  the  iron,  and  an  equal 
amount  for  the  iron  sand  always  found  in  the  cement,  we  should  have  a  further 
deduction  of  41,324  pounds.  It  may  be  that  ore  roasted  in  the  lump  contains 
more  free  acid  than  that  roasted  in  bricks,  which  was  used  in  obtaining  the  liquor 
analysed.  It  is  a  little  remarkable,  however,  that  the  formation  of  iron  salts  in  a 
liquor  which  contains  oue-half  per  cent,  or  more  of  free  sulphuric  acid  can  be 
prevented  by  the  addition  of  so  infinitesimal  amount  of  free  acid  as  14  liters 
to  16$  cubic  meters;  equal  to  16,750  liters  of  liquor. 

3.  A  third  improvement  suggested  is  the  precipitation  of  the  copper  as  a  sul 
phide  from  the  cement  liquor.  To  do  this,  bydroge*n  sulphide  would  be  made  by 
heating  the  rich  pyrites  with  sulphuric  acid,  or  passing  steam  over  hot  pyrites,  the 
resulting  HZ  S  being  dissolved  in  water  contained  in  a  large  chamber.  The 
cement  liquor  would  drop  into  this  liquid  and  the  copper  be  resolved  into  sulphide 
which  would  then  be  smel-ed.  The  objections  to  this  method  are  the  magnitude 
of  the  chambers  and  generators  for  hydrogen  sulphide  which  would  be  required 
to  treat  about  345, 0®0  cubic  feet  of  cement  liquor  yearly  ;  the  necessity  of  manipu 
lating  the  copper  sulphide  rapidly  to  prevent  its  taking  tire,  and  oxidizing  to  copper 
oxide  which  cannot  be  worked  in  the  furnace  without  loss,  and  the  d  fficulty  of 
handling  and  compressing  so  large  a  mass  of  sp  ngy  sulphide.  Assuming  the 
yield  of  1865  as  a  basis  we  have  the  following  estimate  of  what  would  be  required 
for  this  process  : 

231,000  Ibs.  copper  requires  116,600  Ibs.  sulphur  to  make  copper  sulphide. 
116,600  Ibs.  sulphur  requires  220,000  Ibs.  pyrites  to  furnish  the  sulphur. 
116,600  Ibs.  sulphur  makes  1,400,000  cubic  feet  of  H2  S  gas. 
One  volume  water  absorbs  3  volumes  H2  S. 
Water  required,  470,000  cubic  feet 
Or  1,513  cubic  feet  daily  for  310  days.  . 

As  the  amount  of  cement  liquor,  in  1869,  was  only  345,087  cubic  feet,  the 
volume  of  hydrogen  sulphide  solution  would  be  more  than  that  of  the  cement 
liquor.  The  iron  sulphate  would  no  longer  crystallize  out.  Its  production 
would  have  to  be  given  up  or  the  liquor  concentrated  again  by  boiling,  which, 
considering  its  extreme  dilution,  would  not  be  profitable.  Thus  Agordo  is  con 
sidering  one  proposition  to  greatly  increase  its  production  of  copperas  and  an 
other,  which  may  do  away  with  it  altogether. 

The  circumstances  by  which  the  works  are  surrounded  are  such  that  there  is  no 
great  difference  in  economy  betwsen  these  two  diverse  proceedings.  The  town  in 
situated  BO  far  from  routes  of  travel,  that  the  pron  a  on  c  pperas  are  nearly 


18  AGOHDO. 

swallowed  np  by  the  freights  ;  so  that  a  very  slight  improvement  in  <ho  yield  of 
copper,  or  in  the  cost  of  working  it,  might  determine  the  sacrifice  of  the  crystal 
lization  part  of  the  process.  On  the  other  hand  the  demand  for  copperas  is  good  ; 
increased  make  will  cheapen  processes,  and  if  a  great  improvement  in  yield  and 
cost  can  be  obtained  by  a  method  which  gives  more  of  this  article,  there  will  lx> 
an  advantage  in  making  it.  This  advantage  will  be  increased  by.  the  fact  that 
Bignor  BE  HUBERT'S  method  gives  a  fine  product. 

4.  The  manufa  tare  rf  cast  or  wrought  iron  from  the  residues  of  the  lixiviation 
vats,  is  another  suggestion  which  was  under  consideration .  These  residues,  aa 
now  produced,  would  give  a  cast  iron  containing  about  6  per  cent,  of  sulphur,  which, 
with  the  present  process,  would  do  no  harm.  By  the  new  method  of  roasting, 
the  percentage  of  sulphur  would  be  very  much  less  and  would  indeed  be  as  low 
as  that  of  iron  made  from  many  good  brown  hematite  ores.  As  the  consumption 
of  iron  is  about  300  tons  a  year  and  it  could  be  made  at  the  works  for  less  than 
$20  a  ton,  while  it  now  costs  $30,  the  saving  would  be  considerable.  With  the 
new  system  of  roasting  there  is  in  fact  no  reason  why  good  iron,  which  would 
readily  find  a  market,  should  not  be  made.  If  wrought  iron  is  made,  an  open  fire 
will  be  employed  and  the  uuharnmered  bloom  used  instead  of  the  pig. 

In  1869  the  recommendations  of  Signor  PEKLATI  were  confined  to  the  manu 
facture  of  bricks,  and  the  erection  of  a  blast  furnace  to  make  cast  iron.  The 
other  proposals  were  under  discussion. 

The  importance  of  these  changes  can  be  seen  at  a  glance,  by  comparing  the  cost 
of  the  old  and  new  works.  In  doing  this  I  will  assume  that  the  manufacture  oi 
bricks  requires  the  same  amount  of  labor  as  breaking  out  the  kernels.  We  would 
have  on  the  one  hand  the  old  process  comprising  the  7  operations  already  given, 
on  the  other,  the  new  process  with  4  operations  as  follows  :  Boasting,  Lixiviation, 
Fining  and  Cementation.  There  would  be  a  saving  upon  each  ton  of  ore  of  about 
half  a  day's  labor,  13  bushels  of  charcoal  and  most  of  the  sandstone.  This 
assumes  that  the  efforts  to  precipitate  in  such  a  way  as  to  obtain  finable  copper 
are  successful. 


The  importance  to  this  country  of  a  cheap  method  for  the  extraction  of  copper 
can  hardly  be  over-stated.  There  is  a  vast  quantity  of  2  and  3  per  cent,  ore  in  the 
United  States,  lying  in  deposits  that  are  already  known,  and  scattered  through  all 
the  States.  Cheap  and  excellent  processes  are  already  in  use,  though  not  gener 
ally  so.  There  are  no  statistics  available  for  making  an  exact  comparison  between 
the  cost  by  them  and  by  the  Agordo  method.  All  that  can  be  pointed  out  now  is 
the  differences  inherent  in  these  systems.  One  works  with  a  very  great  economy 
of  iron,  and  the  other  makes  sulphuric  acid  as  a  by-product.  In  efficiency  and 
cheapness  they  nre,  so  far  as  I  know,  very  nearly  on  a  par. 

The  advantage  of  the  Italian  method  is  the  extremely  low  cost  of  the  plant. 
When  the  contemplated  changes  have  been  made,  this  expense  will  be  confined  to 
the  erection  of  a  few  rough  roasting  sheds,  lixiviation  vats,  and  a  fining  furnace, 
if  the  amount  "f  ore  will  warrant  it.  The  outlay  for  plant  which  the  other  systems 
require,  is  offset  at  Agordo  by  the  interest,  on  the  cost  of  mining.  This  interest, 
for  9  mouths,  at  one  per  cent,  a  month  would,  on  ore  that  cost  $2.50  to  mine, 
amount  to  23  cents  a  ton,  and  on  ore  that  costs  $10  to  mine,  (as  it  often  does  in 


AGORDA.  1C 

the  West)  90  cents  a  ton.     The  other  expenses  by  the  new  method  will  be  about 
as  follows : 

EXPENSE    PER   TON. 

Labor  Wood-           Charcoal        Iron                 Sand 

days.  cords.              bushels,       pounds.            pounds. 

Making  bricks 0-7 

Roasting  bricks 0-3  0  O03                                                                          I 

Cementation 0-15  0-030                                      18 

Fining 0-12  2                                      10        * 


Total 1-27  0-033  2  18  10 

To  this  there  would  be  a  small  addition  for  crushing  which  could  be  done  by  a 
Blake  or  other  coarse  crusher. 

The  copperas  which  is  a  by-product  of  this  method,  would  be  valuable  only 
when  the  mine  was  so  situated  as  to  enjoy  cheap  and  abundant  transportation. 

It  should  be  noted  that  this  process  is  applicable  to  other  and  more  valuable 
metals  than  copper.  The  careful  roasting  which  retains  97  per  cent,  of  the 
copper  in  the  form  of  soluble  sulphate  would  be  equally  effective  with  nickel  and 
more  so  with  cobalt  These  metals  or  a  mixture  of  them  with  copper  or  iron 
pyrites  can  be  treated  by  this  process  and  app  irently  with  great  success.  In  fact 
ores  that  contain  too  little  of  them  to  be  utiiizable  by  ordinary  methods,  ought  to 
be  valuable  when  brought  under  this  treatment 


THE  MERCURY  WORKS  AT  VALALTA.1 


A  FEW  miles  from  Agordo  there  is  a  mercury  mine,  and,  connected  with  it,  an 
establishment  for  treating  the  ore  which  offers  some  peculiarities  well  worth  con 
sidering.  This  is  the  mine  and  works  of  Valalta.  The  mercury  is  obtained  from 
cinnabar  found  disseminated  generally  in  minute  threads  and  spots  through  a 
mass  of  decomposed  porphyry.  The  rock  also  contains  iron  pyrites  and  gypsum, 
the  latter  being  usually  in  contact  with  the  cinnabar  when  it  is  concentrated  in 
Bmall  veins,  as  sometimes  occurs.  Hand  specimens  of  pure  cinnabar  are  found, 
but  they  are  rare.  As  at  Agordo,  this  deposit  attracts  the  attention  of  the  metal 
lurgist  chiefly  on  account  of  its  poverty,  and  the  means  used  to  work  successfully 
an  ore  of  so  little  value 
Three  sorts  of  ore2  are  obtained  by  hand  picking  as  follows  : 

Good  containing 2-5  per  cent,  mercury 

Poor        "  0-25      ••  " 

Powder    "  0-25      " 

In  one  year  4,910,000k.  or  5, 400  tons  of  ore  were  mined,  and  the  mercury  ob 
tained  was  17,000  k.  or  18-7  tons  which  gives  an  average  yield  of  0-346  per  cent 
The  loss  as  ascertained  at  the  works  was  0*10  per  cent  calculated  upon  the  ton  ot 
ore,  so  that  the  value  of  the  ore  is  as  follows  : 

Yield     0-346  per  cent. 

Loss 0-10 

Mercury  in  ore 0'446      " 

It  has  been  found  that  ore  containing  no  more  than  one-eighth  of  one  per  cent 
can  be  worked  in  this  furnace.  The  methods  by  which  an  ore  containing  only 
4o-100ths  of  one  per  cent,  is  treated  with  profit,  are  as  follows  : 

The  works  are  so   situated  that  the  sorted  ore  is  run  in  cars  on  a  tramway 

1.  For  the  information  contained  in  this  paper  I  am  indebted  to  Signor  MANZONI,  of 
Agordo,  lessee  of  the  works,  and  to  Signor  TOME,  manager. 

2.  A  fuR  suite  of  ores  and  products  of  the  distillation  works  can  be  seen  at  the  New 
fork  School  of  Mines 


VALALTA.  21 

directly  from  the  mine  to  the  top  of  the  furnace,  and  this  work  is  charged  to 
mining  account  At  the  furnace  it  is  thrown  into  a  wood  box,  which  is  so  made 
that  it  can  be  lifted  up,  and  which  is  placed  close  to  a  hopper  which  forms  the 
mouth  of  the  furnace.  In  the  roof  of  the  latter  there  is  a  small  pipe,  with  a  cover 
which  has  a  water  joint  By  looking  through  this  pipe  the  workman  ascertains 
the  condition  of  the  ore  in  the  furnace,  and  by  thrusting  an  iron  rod  through  it 
he  ascertains  the  height  of  the  materials.  The  normal  height  of  the  ore  ia  3  5 
meters  or  11  ft  8  in.  When  it  has  sunk  to  this  level  a  new  charge  is  made,  pro 
vided  the  surface  is  red. 

The  slide  of  the  hopper  is  withdrawn  and  the  charge  alreidyin  it  falls  upon 
the  hot  ore.  The  slide  is  then  closed,  the  iron  plate  which  covers  the  hopper, 
and  which  also  has  a  water  joint,  is  raised,  and  the  new  charge  is  dumped  in  by 
tilting  the  box.  Charcoal,  to  the  amount  of  2  per  cent,  of  the  ore,  is  thrown  ou 
top  and  the  cover  is  replaced.  The  weight  of  the  charge  is  480  to  560  k.— 1056  — 
1232  Ibs. — and  a  new  charge  is  made  usually  every  hour  and  a  quarter.  The 
daily  work  of  one  furnace  (24  hours)  is  therefore  9,120  k.  or  10i  tons. 

The  furnace  is  a  shaft,  and  docs  not  differ  from  the  ordinary  HAHNEK  furnace. 
The  ore  rests  upon  a  large  grate  at  the  bottom  and  after  each  charge  the  work 
man  pulls  down  with  a  hook  an  equal  quantity  of  spent  ore.  It  falls  into  an 
iron  wagon,  running  on  a  tramway,  which  is  carried  under  the  furnace  by  means 
of  an  arched  way. 

The  peculiarity  of  this  furnace  is  its  condensation.  This  is  by  tubes  and 
chambers  similar  to  those  employed  elsewhere,  but  the  tubes  are  of  wood  and  the 
mercurial  vapors  are  drawn  through  the  condensers  by  suction,  an  arrangement 
very  important  in  its  results. 

1.  It  produces  perfect  draft,  so  that  there  is  never  a  return  of  the  vnpors  to  the 
furnace  and  out  at  the  furnace  bottom,  as  sometimes  happens  when  the  draft  is 
natural     With  properly  proportioned  chambers  the  condensation  is  therefore  also 
perfect,  and  the  health  of  the  workmen  does  not  suffer  from  inhaling  mercury 
vapor.    In  the  12  years  during  which  this  apparatus  has  been  in  use,  there  has 
been  no  general  sickness,  though  formerly  the  hospital,  usual  to  these  establish 
ments,  had  to  be  maintained  and  was  well  patronized.     But  there  are  now  no 
cases  at  the  works,  except  (I  believe)  one  or  two  which  are  the  result  of  pure 
carelessness,  or  else  remain  over  from  old  times.     Another  proof  of  its  efficacy  is 
the  revival  of  vegetation  in  the  immediate  neighborhood  of  the  furnace.      In 
former  times  the  lessee  had  a  yearly  expense  of  30,000  francs  in  making  good  the 
damages  by  the  fumes  which  escaped  from  his  chimney.     He  is  now  entirely 
freed  from  this  tax. 

2.  It  ensures  a  constant  and  regular  now  of  the  vapors  from  the  furnace  to  the 
discharge  pipe,  and  thus  enables  the  means  of  condensation  to  be  properly  pro 
portioned  to  the  quantity  of  fumes,  and  the  rapidity  of  their  discharge. 

3.  It  lowers  the  tension  of  the  products  of  combustion  in   the    tubes  and 
chambers  a  little  below  that  of  the  atmosphere  ;  the  column  of  gases  being  some 
what  retarded  at  the  furnace  end  by  friction  of  the  air  against  the  ore.     For  this 
reason  when  the  traps  in  the  tubes  are  opened  there  is  no  discharge  of  vapors,  but, 
on  the  contrary,  an  entrance  of  air.     The  workmen  are  therefore  able  to  collect 


22  TALALTA. 

tha  mercury  and  soot  from  the  tubes  without  stopping  for  a  moment  the  run  of 
the  furnace.  This,  together  with  the  following,  permits  an  uninterrupted  cam 
paign  of  two  years. 

4.  By  keeping  the  amount  of  air  admitted  within  regular  limits,  it  prevents  the 
overheating  of  the  furnace.  If  this  takes  place  the  mercury  vapors  leave  the 
furnace  at  so  high  a  heat  that  the  usual  means  of  condensation  are  insufficient 
and  a  loss  of  metal  ensues. 

It  is  to  the  excellent  condensation  and  the  two  years  run  of  the  furnace, 
that  we  must  attribute  the  economical  results  which  permit  an  ore  containing 
only  9  pounds  of  mercury  to  the  ton  of  2000  pounds,  to  be  worked. 

The  furnace  with  its  arrangements  for  charging,  condensing  and  draft  is  shown 
in  figure  3. 
The  following  are  the  details  of  construction  : 

Furnace  : Height 6'50  meters. 

Diameter. .  -. 1-20        " 

Inclination  of  grate,  about 50° 

Number  of  grate  bars 5 

Width        "        "        0-05  meters 

Length       «        " 1-60        " 

Height  of  gangway  under  furnace 2-20        " 

Width 1'30  meters. 

Sopper  : Height 1-40 

Length  of  mouth. .-. 0-90         » 

Width     "         "    0-30 

Length  of  slide 2.25 

Charging  box  :. .  .Length 1'90  meters. 

Height 0-80 

Width -0-80 

Tubes  : Number  to  1  furnace 3 

Length  of  iron  tubes  in  masonry 1*40  meters. 

"     wood  tubes,  each  section 1  '70         " 

Number  of  sections  in  each  tube 8 

Diameter  of  tubes,  mean 1  '00  meters. 

Whole  length  of  each  tube  as  set  up ....  ^ 15-40         " 

Thickness  of  wood 0-05        «« 

Inclination 5° 

Condensation  chamters  :  (The  dimensions  given  are  nearly  correct.) 
Number.  Height.  Width.  Length. 

1st  5.50  1-20  3-00 

2nd    '  2-40  1'20  300 

3d 2-65  2-80  3-40 

4th  2-70  *  -oO  3-40 

5th  2-80  2-80  3-40 

6th  ...    :    .2-80  ?  Mn  3-40 

7th 2-30  1'70  3-00 

Cubical  contents,  cubic  feet 5.082 

Square  feet  of  external  surface 2,000 


YAIALTA. 


23 


24  VALALTA. 

Chimney  : Feight  from  arch  of  7th  chamber  .10-00 

Length  of  wood  pipe 10-20 

Diameter     "        "    at  too .  0-30 

««  ....    at  bottom 0-25 

Number  of  upright  wood  partitions 2 

The  Furnace  is  built  with  thick  walls  in  order  to  retain  the  heat.  The  outer 
walls  are  built  of  slate  rock  and  the  lining  of  large  red  bricks.  Every  two  years 
the  lining  is  so  worn,  from  friction  of  the  materials,  that  repairs  are  necessary. 
After  the  furnace  is  thoroughly  cool,  the  remains  of  the  old  lining  are  knocked 
out,  from  above,  and  the  new  bricks  are  laid  with  a  cement  composed  of  clay, 
iron  filings  and  acid  water  from  the  condensation  apparatus.  This  water  con 
tains  about  2  per  cent,  of  sulphuric  and  sulphurous  acid.  In  the  outer  walla 
common  mortar  is  used.  While  making  these  repairs  the  workmen  are  employed 
only  2  hours  a  day  to  avoid  sickness  from  inhaling  mercurial  dust,  as  the  bricks 
contain  a  good  deal  of  the  metal.  The  expense  for  repairs  is,  however,  slight 
After  two  years,  the  necessary  repairs  cost  only  150  francs  for  labor  and  50  francs 
ior  material ;  labor  being  worth  about  1—2  francs  a  day.  With  very  hard  bricks 
which  could  resist  the  friction  of  the  ore,  there  is  no  reason  why  the  furnace 
should  not  have  a  still  longer  campaign.  The  first  cost  of  a  double  furnace  with 
two  shafts,  14  condensation  chambers,  6  tubes,  and  the  necessary  arrangements 
for  supplying  water,  is,  in  Valalta,  20,000  francs.  As  before  said,  the  furnace  with 
its  hopper  corresponds  in  all  respects  to  that  invented  by  HAHNEII. 

The  Condensation  Chambers.  Tnose  nearest  the  furnace  are  lined  with  a  cement 
similar  to  that  used  in  building  the  furnace.  It  is  made  of  ground  scoria  2  parts 
and  lime  1  part.  The  scoria  which  is  much  more  serviceable  than  sand,  must 
contain  a  good  deal  of  iron,  as  scorias  from  puddling  or  rehea  ing  furnaces, 
copper  smelting,  etc.  That  used  at  Valalta  is  procured  in  the  copper  works  at 
Agordo.  Those  chambers  which  are  placed  beyond  the  tubes  are  lined  with  wood 
2  inches  thick.  This  is  another  peculiarity  of  these  works.  The  wood  not  only 
forms  a  perfectly  tight  lining  when  it  has  been  properly  seasoned  before  use,  but 
it  affords  cleaner  mercury  and  also  more  of  it  during  the  campaign,  from  the  fact 
that  less  metal  and  soot  cling  to  the  smooth  wooden  surfaces  than  to  a  cemented 
wall.  Thus,  after  the  first  and  second  chambers,  where  the  vapors  are  still  too 
hot  to  permit  the  use  of  a  wood  lining,  the  fumes  have  an  uninterrupted  course 
through  wood  or  wood-lined  passages.  After  many  experiments  with  cements, 
bricks,  etc.,  this  material  has  been  found  the  best. 

The  Tubes  are  also  of  wood,  2  inches  thick.  They  are  made  in  sections,  slightly 
conical  so  as  to  fit  into  each  other.  Wooden  wedges,  driven  firmly  into  the  joints, 
make  the  whole  tight.  Iron  tubes  were  formerly  used;  but  they  made  a  great  deal 
of  trouble,  being  rapidly  eaten  by  the  sulphurous  acid  vapors,  emanating  from 
the  pyrites  in  the  ore.  They  had  to  be  turned  every  12  or  18  months  and  entirely 
renewed  in  2  or  3  years.  Iron  tubes  for  one  furnace  cost  8,000  Austrian  florius  ; 
wood  tubes  2,050  florins.  But  of  this  sum  the  3  iron  rings  on  each  section  of 
wood  tubing  cost  1,200  florins,  and  as  these  remain  uninjured,  the  cost  of  renew 
ing  the  wood  tubing  would  be  only  850  florins,  (about  $357).  But  the  saving  ia 
even  greater  than  this.  Though  the  wood  tubes  are  kept  constantly  wet,  their 


VALALTA.  25 

durability  is  much  greater  than  that  of  iron,  and  I  believe  they  have  been  renewed 
only  once  in  12  years.  A  main  fault  of  the  iron  tubes  is  that  the  soot  obtained 
from  them  is  contaminated  with  iron  dust  and  iron  oxides,  which  makeg  t.ie 
separation  of  the  mercury  from  the  soot  more  difficult,  and  also  introduces  a  cer 
tain  amount  of  iron  into  the  metaL  All  these  advantages— cheapness,  durability, 
and  serviceableuess  — give  to  wood  a  great  superiority  when  it  can  be  used.  Iron 
tubes  are  still  used  for  the  sections  set  in  the  masonry  of  the  furnace  and  the 
chambers,  but  all  other  sections  are  \vood.  It  requires  a  constant  and  pretty 
heavy  flow  of  water,  and  the  wood  must  be  of  a  kind  that  endures  a  condition  of 
moisture  as  long  as  possible  without  rotting.  Fir  and  pine  are  used  at  Valalta.  '  / 

Each  tube  section  is  bound  with  3  iron  rings,  driven  on  to  the  conical  tube. 
Two  trap  doors  are  made  in  each  tube,  one  in  the  top  and  one  in  the  side. 
Through  these  openings  the  workman  with  a  long  handled  hoe,  the  blade  of  which 
is  small,  draws  the  soot  and  mercury  on  the  bottom  of  the  tube  to  one  place  and 
then  removes  it  with  a  scoop.  During  this  operation  his  face  is  protected  by  a 
wet  sponge  placed  over  the  mouth  and  nostrils.  This  precaution  should  never  be 
neglected,  though  when  the  trap  is  opened  the  appearance  of  the  tube  makes  it 
evident  that  there  is  little  danger  of  the  escape  01  vapors.  The  products  of  com 
bustion  are  seen  as  a  bluish  gray,  dense  and  moist  cloud,  moviug  slowly  and 
regularly  through  the  tube,  and  there  is  no  escape  whatever  through  the  open 
trap  ;  an  accident,  which  if  it  occurred,  could  not  escape  observation,  from  the 
strongly  marked  color  of  the  fumes.  But  as  the  workman  has  his  arm  at  times 
partially  immersed  in  this  cloud,  and  his  face  is  therefore  brought  near  it,  the 
necessity  of  using  the  sponge,  as  a  matter  of  precaution,  is  evident.  On  the 
bottom  of  the  tube,  mercury  soot,  and  metallic  mercury  lying  in  small  pools  are 
seen,  the  bright  surface  of  the  metal  reflecting  the  light  which  enters  through  the 
trap,  and  illuminating  the  tube  immediately  around  it. 

The  course  of  the  vapors  is  as  follows  :  from  the  furnace  to  condensation 
chamber  No.  1  which  has  about  the  same  height  as  the  furnace  ;  from  No.  1  to 
No.  2  ;  from  No.  2  through  the  two  lower  tubts,  each  15  meters  long,  to  Nos.  3, 
4,  5  and  6  in  succession.  These  four  chambers  aiv  so  connected  that  all  the  fluid 
mercury  collects  in  No.  5,  whence  it  flows  through  an  iron  pipe  to  a  kettle  placed 
in  a  reservoir  outside,  fed  with  running  water.  Both  metallic  mercury,  and 
mercury  white  collect  in  this  kettle.  Very  little  soot,  and  that  very  poor,  collects 
in  the  chambers  1  and  2  next  the  furnace.  Most  of  it  falls  in  the  two  lower 
tubes,  together  with  some  mercury.  A  good  deal  of  the  latter  flows  into  chambers 
3  and  4,  and  runs  into  the  kettle  above  mentioned.  With  so  long  a  campaign  it 
is  necessary  to  collect  as  much  of  the  metal  produced  as  possible,  while  the  furnace 
is  still  in  operation  ;  and  the  arrangements  at  Valalta  for  doing  this  are  very  per 
fect.  From  chamber  No.  6  the  vapors  pass  through  the  upper  tube  to  No.  7, 
thence  to  the  1st  partition  in  the  chimney,  where  they  rise  to  the  top,  return 
downwards  to  the  second  partition,  rise  again  through  the  3d  partition  and  finally 
leave  the  furnace  by  a  square  wood  pipe  which,  turning  downwards,  rests  upon  the 
side  of  the  chimney,  and  finally  at  the  level  of  the  tubes,  or  a  little  ab  >ve,  opens 
Into  a  water  trompe.  This  has  a  fall  of  5  or  6  meters,  discharging  its  water  upon 
u  wooden  floor  placed  under  the  tubes.  This  floor,  which  is  carefully  made,  .so 


26  VALALTA. 

as  to  be  water-ana  mercury  -tight,  slopes  from  the  furnace  to  the  condensation 
house,  where  the  water  runs  off  th'rouuh  a  trough,  which  in.  its  turn  empties  into 
a  cistern,  in  order  that,  by  arresting  the  rapidity  of  the  flow,  any  mercury  that 
may  have  found  its  way  to  the  floor  may  have  an  opportunity  to  settle.  There 
are  two  ways  in  which  the  metal  may  arrive  on  the  floor  :  1st.  by  leaking  through 
the  joints  of  the  tubes  ;  2nd.  by  escaping  condensation  in  its  cour  e  through  the 
various  passages  until  it  meets  the  stream  of  water.  But  very  little  does  escape, 
however,  only  a  few  drops  ever  appearing  on  tbe  floor  or  in  the  cistern.  I  do  not 
know  that  any  thing  of  importance  has  been  collected  from  those  places. 

The  Charge  consists  of  the  ore  as  it  comes  from  the  mine,  and  ot  bricks  made 
up  of  fine  ore.  Much  trouble  was  experienced  at  first,  in  making  these  bricks 
hard.  It  was  found  that  to  produce  a  good  brick,  which  would  not  fall  to  pieces 
in  the  furnace,  the  ore  must  not  be  coarser  than  one  centimeter  (04  inch)  and 
must  be  cemented  with  some  substance,  like  water  containing  sulphurous  acid,  or 
iron  sulphate,  which  by  attacking  slightly  the  surfaces  of  the  clay  and  gyp>um  in 
the  ore,  would  act  as  a  cement.  The  liquor  in  use  is  that  which  serves  to  con 
dense  the  last  condensable  matters  in  the  fumes,  and  is  said  to  contain  2  per  cent, 
of  sulphurous  acid.  The  bricks  are  made  in  moulds  10  centimeters  (4  inches) 
high,  and  with  a  mean  diameter  of  15  centimeters  (6  inches)-  They  are  dried  on 
iron  plates.  About  one-third  of  the  ore.  is  charged  in  this  form  ;  but  the  charge 
is  sometimes  one-half  coarse  ore  and  one-half  bricks. 

The  Loss  in  working  is,  according  to  the  assays  continually  made  at  the  works, 
224  per  cent.  ;  or  0-10  per  cent,  of  the  ore  upon  a  content  of  0446  per  cent,  of 
mercury. 

The  Products  of  the  distillation  are  :— 1.  Mercury.  This  is  very  pure  and 
brings  the  highest  price.  It  is  all  consumed  in  Italy  and  Austria.  2.  Mercurial 
soot.  This  is  composed  of  mercury  in  the  state  of  powder,  mixed  with  a  little 
ore  powder,  mercury  sulphide,  charcoal  powder,  etc.  It  is  brought  to  nature  by 
rubbing  it  on  an  inclined  table,  when  the  grains  of  mercury  powder  coalesce  by 
friction  and  collect  in  drops  at  the  bottom  of  the  incline.  The  remainder  is 
made  into-bricks  and  re-distilled.  3.  Mercury  white,  which  forms  but  a  very  small 
proportion  of  the  product. 

The  spent  ore,  as  it  is  discharged  from  the  furnace,  is  not  very  hot,  gives  out  no 
vapors  of  mercury  and  only  a  slight  odor  of  sulphur. 

The  Labor  employed  consists  of  2  men  to  each  furnace  ;  length  of  shift  8  hours  ; 
or  6  men  to  24  hours.  They  bring  the  charcoal,  make  the  small  ore  into  bricks, 
charge  and  discharge  the  furnace,  collect  the  soot,  work  it  over  to  extract  its 
mercury,  and  pack  the  mercury  in  sacks  of  kid  skin  which  are  afterwards  placed 
in  small  kegs.  Thus  the  6  men  complete  the  personnel  of  one  furnace.  They  are 
paid  at  Valalta  an  average  of  1  -20  francs  (24  cents)  a  day.  Two  furnaces  require 
a  double  number  of  men. 

The  Fuel  is  pine  and  fir  charcoal  costing   7  francs    a    cubic    meter  ;    or  5 
cents,  coin,  a  bushel,  very  nearly  ;   600  cubic  meters  or  18,875  bushels  are  used 
for  two  furnaces  yearly. 
1  he  Expense  of  Treatment  was  given  by  Signer  TOME  as  follows  : 


VALALTA.  27 

COST   OP  TEEATINQ    10,000   K.    ORE   PRODUCING    34' 6   K.    MBRCTBY. 

Francs.  Proportions. 

Distillation  (labor) ]  5  02  25 

Working  soot 0-05  0-1 

Royalty  paid  on  production 2-30  4-Q 

Materials . : 24-78  42 

Kepairs  :  labor  and  materials 1-35  2-4 

Running  expenses 43-50  73  5 

General  repairs 3-72  G.3 

Administration 11-90  20.2 

Cost  of  distillation 59-12  100*0 

Cost  of  mining 134-73 

Total  cost  of  34-6  k.   mercury 103-85 

Cost  of  1000  k.    ore,  francs . . . 19  -39 

Cost  of  2000  pounds S3 -53 

The  cost  is  therefor  $3-5b  for  one  ton  of  ore  producing  6  92  pounds  of  mercury, 
or  51  cen's  a  pound. 

The  expense  for  abor  and  materials  upon  one  ton  of  ore  (1000  k.)  is  as  follows  ; 
both  labor  and  materials  being  included  under  the  head  of  "repairs." 

Labor.          Charcoal.      Running  General 

Repairs.  Repairs. 

For  1000  k 1 -G4  d.  84  Ibs.         2-7  cents.  7'5  cents. 

Proportionate  parts. 

Total  cost  =  100.  .  33-5  55-20          3-00  8-30 

Mining  cost  per  ton  (2000  Ibs.) $2-45  or  69 

Distilling « 1-08  or  31 

$3-53      100 

Though  comparisons  are  never  more  to  be  distrusted  than  when  made  upon 
ores  of  mercury,  mined  in  distant  districts  and  worked  in  furnaces  more  or  less 
dissimilar,  it  is  nevertheless  instructive  to  set  the  results  of  the  Valalta  furnace 
against  those  in  other  works.  The  distinctive  characteristics  of  the  HAHNEB 
furnace  is,  that  it  is  a  shaft  and  that  it  works  continuously  instead  of  intermit 
tently.  Other  furnaces  are  either  of  the  reverberatory  form  or,  if  they  are  built 
like  a  shaft,  they  are  intermittent,  being  filled,  fired  and  cooled  down  at  each 
operation.  Between  the  HAHNER  furnace  at  Valalta  and  those  at  Idria  in  Austria 
and  Ripa  in  Italy,  theie  are  two  important  differences—  that  of  drawing  air  regu 
larly  through  the  furnace,  which  is  not  done  at  either  of  the  last  mentioned 
places  ;  and  the  condensation,  wrhich  is  by  large  Chambers  and  not  by  tubes,  as 
at  Valalta.  The  work  in  these  furnaces  shows  some  notable  differences. 

At  Idria3  the  ore  is  charged  with  3  to  4  per  cent,  of  charcoal  every  1^  houit*. 

The  ora  contains ,     3-11  per  cent  mercuiy. 

'ihe  yield  is 1'90 

Loss  therefore 1-21  or  38-9  per  cent 

At  Ripa* 

3.  Berg.  &  Hiit».  Ze/unp,  1854,  p.  419. 

4.  Bull.  d.  1.  Soc.  Ind.  Min.  II.,  383. 


28  VALALTA. 

The  charge  in  ^4  hours  is  8,800  pounds. 

Charcoal  352      "      or  4  per  cent 

The  ore  contains  1  per  cent. 

The  yield  is  only  25 — 30  per  cent. 

The  system  of  condensation  by  chambers  is  not  so  thorough  as  that  by  tubes 
and  at  Idria  and  Ripa  the  condensation  is  further  hindered  by  the  excessive 
amount  of  charcoal  used,  amounting  to  50  and  100  per  cent  more  than  at 
Vaialta.  This  must  add  very  greatly  to  the  temperature  of  the  gases.  Whether 
the  regular  and  moderate  flow  of  air  produced  by  the  trompe  would  effect  a  re 
duction  of  the  amount  of  fuel  cannot  be  told  without  experiment.  The  ores  are 
practically  the  same,  except  in  regard  to  richness.  It  should  be  remarked  that 
poorer  ores  at  Idria  require  more  charcoal. 


THE  LEAD  WORKS  AT  MECHERNICH. 


ON  the  left  bank  of  the  Rhine  there  is  a  sandstone  layer  which  covers  a  surface 
several  square  miles  in  area  and  for  a  thickness  of  more  than  100  feet,  contains 
lead  in  the  form  of  sulphide  aud  carbonate.  The  rock  contains  but  little  lead  ore, 
from  2  to  3  per  cent  only,  but  it  is  so  friable  as  to  break  up  to  sand  by  the  mere 
shock  of  the  blast,  and  a  simple  but  careful  concentration  permits  the  treatment 
of  ore  so  poor,  even,  as  this.  Although  this  ore  does  not  resemble  that  which  is  so 
common  in  Utah  and  Nevada,  either  in  mode  of  occurrence  or  in  appearance,  it 
has  about  the  samo  composition.  The  product  consists  of  about  42  per  cent, 
galena,  28  per  cent  lead  carbonate,  and  30  per  cent,  quartz  and  clay.  But  these 
proportione  are  not  exact.  The  amount  ol  silver  varies  from  0*007  to  OO11  per 
cent,  or  2  to  4  ounces  to  the  ton  of  washed  ore. 

The  general  mode  of  treatment  is  by  roast  ing  and  subsequent  fusion  with  puddle 
slag  and  sometimes  with  metallic  iron.  There  are  two  works,  those  of  the  Mecher- 
nich  Company  and  those  of  Messrs.  PIRA.TH  &  JUNO.  Three  kin  Is  of  ore  are  ob 
tained.  Smelting  ore,  "glasur"  ore  used  for  glazing  earthenware,  and  white- 
lead  ore,  part  of  which  is  worked  up  to  paint  by  RHODIUS  BROTHERS,  near  Linz, 
on  the  Rhine,  by  means  of  the  gas  which  issues  from  natural  gas  wells. 
THE  MECHERNICH  COMPANY.' 

RAMMEIASBEBG  gives  the  following  proportions  as  the  average  product  of  these 
sorts,  at  this  establishment  :* 

Smelting  ore 20,900  tons  containing       58         per  cent  lead. 

Glazingore 1,925         "  "         62—80          "        " 

White  lead  ore 660         "  "         50-52          "         " 

BOASTING. 

The  ore  is  roasted  in  furnaces  which  have  a  hearth  33  feet  long  and  12  feet  6 

1.  For  information  contained  in  these  notes  on  Mechernich,  I  am  indebted  to  Herr 
EKENHUT,  chemist  to  the  company. 

2.  A  full  ffuite  of  the  ores  and  furnace  products  of  the  Mechernich  Company  are  in  th« 
cabinet*  of  the  New  York  Hchoul  of  Mines, 


30 


MECHERNICH. 


inches  wide.  The  roof  is  made  of  hollow  bricks  to  lessen  the  weight  and  the 
enormous  thrust  of  an  arch  so  very  flat,  a  weight  which  soon  causes  the  falling  in 
of  an  ordinary  roof.  These  bricks  are  13i  inches  square,  9  inches  high,  and  have 
a  deep  depression  in  their 'upper  surface  so  that  probably  two-fifths  of  the  material 
is  removed.  The  doors  are  formed  of  a  cast-iron  frame  set  in  the  brick  work,  the 
iVame  being  2  feet  long,  1  foot  high  and  with  an  opening  8  inches  square.  This 
opening  is  closed  by  a  cast-iron  plate. 


Figure  4.  Figure  5. 

Figure  4  shows  the  form  of  the  bricks  and  figure  5  that  of  the  iron  castings  for 
the  doors. 

A  cast-iron  box  on  the  top  of  the  furnace  receives  the  ore  while  it  is  drying. 
About  ninety  centners  or  9,900  pounds  are  charged  every  12  hours,  so  that  the 
furnace  roasts  9  to  10  tons  daily.  The  rapidity  of  the  roasting  depends  somewhat 
upon  the  proportion  of  carbonate  in  the  charge.  When  there  is  much  of  this, 
the  roasting  is  rapid  ;  and  the  large  amount  passed  through  these  furnaces  is  also 
due  to  this  ore.  At  Freiberg,  where  the  ore  is  altogether  sulphide,  the  furnaces 
cannot  work  so  much.  The  Mechernich  works  have  10  of  these  furnaces. 

The  management  of  these  furnaces  is  peculiar.  The  ore  lies  in  a  much  thicker 
layer  than  is  usually  allowed,  and  toward  the  fire-place  it  is  heaped  up  nearly  to 
the  roof,  in  the  c«uter  sloping  away  to  the  sides,  where  the  gases  mostly  pass. 
Next  the  fire-place  there  is  a  depression  in  the  hearth,  called  the  crucible,  de 
signed  to  receive  the  ore  which  is  completely  melted  toward  the  end  of  the  opera 
tion.  The  ore  forms  a  broad  bank  at  the  edge  of  this  crucible,  and  in  immediate 
contacv  with  the  flames.  It  smelts  rapidly,  an!  as  fast  as  the  melted  ore  runs 
down  into  the  crucible  the  ore  behind  it  is  pushed  forward. 

But  it  is  evident  that  this  method  of  treatment  is  not  favorable  to  the  liberation 
of  the  sulphur,  a  process  which  demands  the  most  complete  access  of  air,  and 
access  is  prevented  in  these  furnaces  by  the  extreme  thickness  of  the  ore  layer. 
Accordingly  wo  find  that  although  the  ore  cannot  contain  more  than  5  per  cent, 
sulphur,  as  a  great  part  of  it  is  already  oxidized  and  there  is  no  pyrites  present, 
the  roasting  is  still  far  from  perfect.  When  the  ore  arrives  at  the  crucible  it  does 
so  with  its  galena  probably  not  more  than  half  roasted  and  the  melting  down  of 
the  fine  and  intimately  mixed  quartz  and  lead  oxides  is  then  so  rapid  that  the 
galena  is  covered  with  a  glaze  of  slagged  ore.  It  is  carried  down  with  the  latter 
into  the  crucible  and  forms  a  layer  under  it  I  should  judge  the  furnaces  were 
producing,  at  the  time  of  my  visit,  fully  20  per  cent,  of  this  unaltered  galena. 

This  artificial  galena  is  very  much  richer  in  silver  than  the  ore  which  has  been 
converted  into  silicate ;  a  circumstance  which  is  due  to  the  stronger  chemism 
between  silver  and  sulphur  than  between  silver  and  oxygen.  An  assay  was  made 
at  my  suggestion  of  the  oxidized  ore  and  the  unaltered  galena  from  a  furnace, 


MECHERNICH. 


31 


which  unfortunately  for  the  trial,  was  running  on  very  poor  ore,  containing  about 
25  per  cent.  lead.  , 

I.  The  unaltered  galena  contained  0-055  per  cent  silver  or  7 '3  ounces  per  ton. 
II.  The  lead  silicate  "  0-008         "         •«         «•    2-3 

To  prevent  the  formation  of  this  product  a  new  furnace  has  been  built.  It 
has  two  hearths,  an  under  and  an  upper,  with  75  feet  of  hearth  length.  This 
is  a  success  in  so  far  as  its  roasting  is  better,  its  product  being  an  almost  com 
pletely  homogeneous  silicate,  with  but  fow  particles  of  galena  distributed  through 
it.  in  repeating  tais  experiment  a  furnace  has  been  built  with  a  total  length  of 
hearth  amounting  to  nearly  &2  feet  The  result  has  not  been  made  public.  There 
is,  however,  one  difficulty  connected  with  the  reduction  of  the  sulphur  to  so  small 
an  amount  Under  the  old  circumstances  a  certain  quantity  of  matte,  about  2 
per  cent  of  the  charge,  was  formed  and  collected  at  the  bottom  of  the  conical  pots 
used  to  receive  the  slag.  But  a  less  quantity  than  this  would  probably  elude  col 
lection  and  have  to  be  thrown  on  the  waste  heap  with  the  slag.  A  certain  amount 
of  matte  is  always  retained  by  the  slag,  either  in  solution  or  in  minute  drops 
mechanically  held.  If  the  sulphur  ccn  be  reduced  to  the  amount  which  the  slag 
has  always  retained  in  this  manner,  there  would  certainly  be  a  gain  ;  but  if  the 
liberation  of  the  sulphur  is  not  carried  so  far,  but  still  far  enough  to  make  the  col 
lection  of  the  matte  impracticable,  there  would  be  a  loss. 

In  roasting  by  the  former  method  it  was  impossible 
to  ascertain  the  progress  of  the  opera; ion,  for  the 
mass  of  ore  in  the  furnace  was  by  no  means  homo 
geneous.  The  amount  of  galena  which  passed  un 
changed  through  the  operation  proved  that  it  was  very 
incomplete.  la  the  new  furnace,  however,  the 
amount  of  sulphur  liberated  can  be  ascertained  ;  and 
with  ore  containing  6  -5  to  7  -5  per  cent,  sulphur,  cor 
responding  to  48-5  and  56  per  cent  galena,  the 
roasted  ore  has  1-5  to  1  per  cent,  corresponding  to 
11'2  and  7*5  per  cent  galena.  The  larger  of 
these  quantities,  1-5  per  cent,  sulphur,  corresponds 
to  an  amount  of  matte  equal  to  about  6  per 
cent  of  the  ore  ;  but  this  would  be  very  much  les 
sened  by  the  sulphur  dissolved  in  the  slag.  Assum 
ing  that  only  one-halt  the  sulphur  was  formerly  eli 
minated  in  roasting,  we  find  that  about  3-5  per 
cent  of  sulphur  in  the  shaft  furnace  gave  about  2 
percent,  of  the  matte.  Reduced  to  1-5  per  cent,  the 
sulphur  would  probably  all  be  absorbed  by  the  slags, 
and  the  new  method  would  therefore  be  advantage 
ous.  It  is  hoped,  however,  that  the  ore  can  be 


Figure  G.       T.eart    fur 
nace  at  Slecttrrnich. 


A — Charging  Poor. 

entirely  freed  from  sulphur,  or  the  latter  reduced  to  less  than  one    per  cent  at 
most,  and  in  that  case  there  would  be  a  considerable  saving  by  the  better  roasting. 

FUSION. 
The  Furnaces  in  which  the  roasted  ore  is  smelted,  arc  shown  in  figure  6.     They 


32  MECHERNICH. 

are  built  of  ordinary  red  brick.  They  are  15  feet  high,  and  4  feet  square,  and 
have  4  water  tuyeres,  which  are  of  the  built  up  kind,  the  back  piece  being  bolted, 
instead  of  cast,  on.  These  tuyeres  have  been  discarded  in  most  works.  The  fur 
naces  are  closed  at  the  top  by  a  brick  flue,  the  gases  being  led  to  high  chimnies 
which  complete  the  system.  Other  dimensions  are  as  follows  : 

Height  of  furnace 15  feet 

Section,  square 4  X  ^     " 

Height  of  slag  hole  above  tap  hole 14  inches 

"     "  side  tuyeres  above  slag  hole 10     " 

"     •'  back  tuyeres  above  side  tuyeres 6     " 

"     "  "  "    tap  hole 30     " 

Length  of  tuyer 30     " 

Diameter  of  tuyer  outside 14     " 

•'  "     interior 1|  " 

Material  of  furnace Ked  brick. 

f  Coal  ashes. 

Material  of  hearth,  brasque  made  of -J  Clay. 

(  Coke  dust 

A  round  furnace  had  just  been  finished  at  the  time  of  my  visit,  designed  accord 
ing  to  the  principles  which  gave  such  success  to  the  Freiberg  furnaces.  Its 
dimensions  were  as  follows  : 

Height 15  feet 

Diameter  at  top 6     «* 

«'        of  hearth 4     " 

Air  is  supplied  at  a  pressure  of  9  inches  of  -renter  by  two  fans  made  after  especial 
designs.  They  have  the  usual  tapering  vanes  and  do  extremely  good  service. 
Their  dimensions  are . 

Diameter 5  feet  6  inches. 

Width  of  blades  at  center  of  fan 10      " 

"  "     "    circumference 6      " 

Diameter  of  conducting  pipe 10      " 

[Revolutions  per  minute,  maximum 1200      " 

««  "         "      when  regularly  working  800 

Only  one  fan  is  in  constant  use,  the  other  being  kept  in  reserve.  In  the  blast 
house  the  pressure  is  10i  to  11  inches  of  water,  which  diminishes  to  9  at  the  fur 
naces.  At  the  time  of  my  visit  this  ian  supplied  5  shafts  and  1  cupel  furnace. 

The  Charge.  It  has  been  found  that  a  slag  which  is  to  be  free  from  lead  must 
contain  at  least  40  per  cent,  of  oxide  of  iron,  and  as  the  Mechernich  ore  contains 
none  of  this  metal,  its  only  impurity  being  a  very  small  amount  of  copper,  iron 
has  to  be  added  to  the  charge  in  some  form.  For  this  purpose  puddle  slag  is 
brought  from  Eschweiler  near  Belgium,  and  when  t!'ere  is  any  raw  ore,  or  much 
unoxiclized  galena  in  the  charge,  a  small  quantity  of  cast-iron  is  also  added. 

The  charge  is  made  up  as  follows  : 

Boasted  ore 56—58  per  cent,  lead 100 

Puddle  slag 50 

Limestone 48 

Iron 2-5        203 

Coke  =  9-9  p.  c.  of  charge  or  20  p.  c.  of  ore ...  20 


MECHERNICH.  33 

At  the  time  when  the  charge  above  given  was  taken  down,  the  works  were 
compelled,  for  lack  of  sufficient  number  of  laborers  at  the  roasting  furnaces,  to 
add  raw  ore,  which  accounts  for  the  iron  in  the  charge.  It  will  be  observed  that 
the  amount  of  coke  used  is  very  small,  a  consequence  of  the  fusibility  of  roasted 
lead  ore.  About  35  tons  oi  charge  are  smelted  in  24  hours. 

Products.    From  this  operation  are  obtained  : 

Lead  containing  0-014—0-027  per  cent  silver  or  4 — 8  ounces  to  the  ton. 
Matte  containing  10  per  cent.  lead. 
Slag  containing  0  -75  —1  per  cent  lead. 

The  slag  is  received  in  iron  pots  2  feet  high,  16  inches  in  diameter  at  the  top 
and  6  inches  at  the  lower  end.  In  these  the  matte  settles  to  the  bottom,  nearly 
every  block  yielding  10—25  pounds.  But  to  make  this  settling  of  the  matte  sure, 
it  is  indispensable  that  the  pot  be  rapidly  tilled.  When  this  system  of  dra wing- 
off  slag  was  first  introduced,  several  trials  were  deemed  unfavorable  which  failed 
only  because  the  slag  was  allowed  to  drop  slowly  into  the  pot,  and  the  lower  half 
of  the  contents  became  solid  before  the  upper  half  ran  in.  Perfect  fluidity  of  the 
mass  is  necessary  for  the  settling  of  the  matte,  and  for  this  reason  the  furnace 
must  be  a  closed  one  ;  a  form  which  has  many  advantages  besides  the  collection 
of  small  quantities  of  matte  wbich  might  otherwise  be  lost 

DESIXVEBIZATION    OF   THE    LEAD. 

In  former  times  three  out  of  the  five  systems  of  desilverization  by  zinc  were 
practiced  at  Mecheruich  and  in  its  neighborhood.  The  differences,  ae  with  all 
these  methods,  were  iu  Uio  method  of  dezincing  the  lead  after  the  silver  had 
been  removed.  Thei>«  three  methods  will  be  considered  in  describing  this  and 
the  following  works. 

At  Mechernich  the  kettles  hold  11  to  12  tons  each.  The  zinc  amounts  to  one 
and  one-twelfth  percent,  of  the  lead  and  is  added  in  3  portions  :  (1)  0-75  per 
cent. ;  (2)  0  25  per  cent.  ,  (3)  0  083  per  cent.  On  11  tons  this  is  1G5  55  and 
184  pounds  ;  total  2384  pounds.  The  zinc  alloy  is  ladled  into  moulds  aud  the 
pigs  are  heattd  in  a  tube  slightly  inclined.  By  raising  the  temperature  gradually 
a  good  deal  of  the  lead  runs  out,  leaving  an  alloy  much  richer  in  bilver.  Toward 
the  end  of  the  operation  the  alloy  is  stirre  1  with  a  rod  until  it  becomes  quite 
"  dry,"  and  has  the  form  of  lumps  or  shot  It  is  then  melted  and  cast  Its  silver 
now  amounts  to  1-5  to  2-5  percent,  but  much  richer  alloy  is  sometimes  ob 
tained. 

The  lead  which  runs  from  this  tube  contains  0-012 — 0-020  per  cent  silver  and 
passes  again  through  the  process  of  desilverizttion. 

Treatment  of  the  rich  alloy.  These  works  long  retained  *he  old  method,  rejected 
everywhere  else,  of  fusing  the  rich  alloy  with  puddle  slag  to  reinov^  the  zino. 
The  fusion  of  silver  at  a  high  temperature  in  the  presence  of  zincsh  ulrl,  accord 
ing  to  all  laws  of  metallurgy,  be  an  opera' ion  attended  with  considerable  loss, 
and  great  care  was  taken  to  make  this  as  smalt  as  possible. 

T.ie  furnace  was  10  feet  high  and  2i  feet  square,  and  had  3  tuyere*.  It  wis  first 
started  with  puddle  slag  alone,  and  when  this  was  flowing  freely,  the  alloy  was 
charged. 

To  100  of  alloy  90  parts  of  puddle  slag  were  added  and  smelted  with  17—18 
coke.  The  pressure  of  the  blaht  must  not  be  more  than  6  inches  of  w^ter. 


84  MECHERNICH. 

Abor.t  7,700  pounds  of  this  mixture  were  smelted  in  24hours,  and  the  loes  ia  said 
to  have  been  not  mere  than  1  per  cent,  of  lead  at  the  outside. 

The  poor  lead  is  de-zinced  in  a  similar  manner.  It  is  charged  with  puddle 
slag  in  the  proportion,  of  100  lead:  4  to  6  puddle  slag,  and  3  to  4  coke.  It  is  then 
poled  and  cast.  It  is  very  pure,  as  the  ioilowing  analysis  by  Mr.  EISENHUT, 
chemist  to  the  Company,  shows  : 

Silver 000025 

Copper. 0-0025 

Antimony 0-0050 

Iron 0 -0030 

Zinc trace. 

Nickel 0-0021 

Lead  by  difference 99  98715 

100 

THE  NEW  PROCESS. 

Within  three  years  the  method  pt  de-zincing  by  steam  has  been  introduced  at 
Mecheinich.  \Vhen  the  third  allo]  has  been  taken  off,  steam  is  introduced  lor 
two  hours,  the  lead  being  kept  at  a  red  heat,  and  covered  with  a  close  hood. 
Then  the  hood  is  opened  to  allow  the  air  to  euter  and  the  passage  of  nteana  is 
continued  one  hour,  to  remove  the  antimony.  The  new  method  produces  more 
scraps  but  saves  in  labor.  Its  chief  advantages,  however,  are  the  more  perfect 
removal  of  antimony  and  the  complete  removal  ot  the  nickel,  which  by  the 
analysis  last  given  is  seen  to  be  present  in  small  quantity.  What  alteration  the 
change  has  had  upon  the  quality  of  the  lead  is  to  be  seen  from  the  following 
arerag<»  of  two  analyses,  made  by  Mr.  EISENHUT  upon  lead  produced  by  the  steam 
process  : 

Silver 0-00052 

Copper    0-00175 

Antimony 0-00405 

Iron 0  00064 

Lead  by  difference 99  9931)4 

100 

The  rich  lead,  now  freed'  of  its  zinc,  is  poled  for  one  hour  in  a  kettle,  and 
cupelled  in  an  English  furnace,  having  the  ordinaiy  elliptical  test,  with  axes  of 
3  and  4  feat.  The  run  lasts  5  to  6  d.tys,  13,000  pounds  we'ght  of  lead  is  cupelled. 
and  the  'button  of  silver  weighs  about  150  pounds.  The  tuyere  ia  a  pipe  2 
inches  high  and  6  inches  wide,  the  blast  parsing  through  a  zinc  pipe  3 — 4  inches 
in  diameter.  It  is  the  experience  of  many  works,  that  a  large  tuyere  oi'  this 
kind  mnkes  poorer  litharge  than  one  with  a  narrower  orifice. 

Treatment  of  the  Matte.  Matte  amounting  to  about  2  per  cent,  of  the  ore's 
weight  is  obtained  from  the  fusion  of  the  ore.  It  is  roasted  and  smelted  with 
lead  scraps  to  second  quality  lead.  This  contains  more  antimony  than  the  first 
lead,  but  still  considerably  less  than  one  percent,  though  sufficient  to  give  it  a 
silvery  whiteness.  It  is  partly  made  up  into  shot,  an  old  shaft  in  the  mine 
serving  for  a  shot  tower,  and  the  shot  being  made  on  English  and  American 
account. 


MECHERNICH.  35 

THE  COMMERN  WORKS. 

.  PIRATH  &  JUNO  have  a  similar  establishment  in  Commern  near  Mech- 
ernicb,  and  treat  ore  from  the  same  sandst  >na  Uyer.  Their  mine,  howuver. 
produces  less  galena  iu  proportion  to  the  lead  carbouute  than  the  other,  and 
they  consequently  have  le*8  unaltered  galena  in  the  ro  isied  ore.  The  record  •••( 
two  of  their  roc  sung  furnaces  for  three  weeks  is  interesting  : 

Furnace  No.  I.  Furnace  No.  II. 

Coal  Ibs.         Ore  Ibs.  Coal  Ibs.          Ot><  Ibs. 

August? 28400  180.500  32200  18(5500 

"     14 30400  176,000  31800  188750 

"    21 29,400  190,000  30,200  203.000 


88200  546  500  94,230  578,250 

Total  ore  roasted 1,124.750  Ibs. 

"      coal  consumed 182400     * 

This  amounts  to  a  consumption  of  16  21  pel  cent,  of  ecu!,  and  a  daily  product 
of  53,580  pounds  from  two  iurnaoe*.  Tiiere  are  no  analyses  of  the  roasted  ore 
at  baud  but  its  composition  is  precty  nearly  :  silion35,  lead  oxide  55.  clay,  iron, 
sulphur,  copper  and  antimony,  10.  Liuientoue  is  sometimes  added  iuroustiug  j 
but  only  where  there  is  too  little,  lead  present. 
The  lurnaces  have  the  following  dimensions  : 

Height 14  feet 

Section 4y4 

Tuyeres 4 

"        height  above  tap 17  inches 

The  material  is  red  brick  and  the  campaign  usually  last  3  to  4  months.  The 
charge  is  composed  of 

Roasted  ore 44,000  pounds. 

Unroasted  ore 9,900 

Limestone 18,900         " 

Puddle  slag 27,500 

Coke  11  —  12  per  ceut 11,660—12  6*0 

The  amount  reported  to  be  p.issed  through  these  furnaces  daily  is  enormous  ; 
amounting  to  132.000—143,000  pound*,  and  if  the  Mechernich  work',  with  the 
same  ore  and  the  same  furnaces  smelt  only  38i  t:»ns  in  24  hours  with  10  per 
cent,  of  coke,  it  is  hardly  possible  that  the  Com  cue  ru  works  put  through  6610  71 
tons  with  11  to  12  per  cent,  of  iuel.  The  latter  qu»nti<its  are  !ul*y  equal  to  the 
largest  charges  tue  much  larger  furnaces  of  Freiberg  have  run  through,  wheu 
tlu-  ohmrge  consisted  almost  entirely  of  fusible  slag. 

Each  furnace  at  Commern  produces  27,500— 28.600  pounds  of  lead  daily. 
Tue  slag  is  reported  to  contain  0-3—0-4  percent  kad.  and  the  lead  about  6 
ounces  to  the  ton. 

Iu  the  method  of  desilveri  nation  (before  the  introduction  of  the  steam  pro 
cess)  there  were  some  differences  from  that  pursued  at  Mochemich.  Alter 
rseltiug  in  the  kettle  the  lead  way  first  poled  to  remove  all  impurities.  Poling 
consists  in  plunging  a  stick  of  green  wood  in  the  melted  metal,  which  is  hot 
enough  to  ciiar  i:  rapidly.  It  gives  out  a  gre.it  quantity  of  gas,  partly  composed 


36  MECHERNICH. 

of  steam  from  tb9  large  amount  of  water  contained  in  green  wood  and  partly 
carburetted  compounds  reeultmg  from  the  decomposition  of  the  fibre.  Tho 
escape  of  these  gases  throws  the  bath  into  violent  ebullition  and  every  part  of 
the  metal  is  brought  to  the  surface,  where  the  lighter  alloys  of  iron  and  copper 
with  zinc  remain.  As  at  the  neighboring  works  1-08  per  cent,  of  zinc  is  added 
in  three  operations,  but  the  amounts  are  varied,  being  1st.  0*66  per  cent.,  2nd. 

0  34  per  cent.,  3d.  0-083  per  cent. 

The  chief  point  of  difference  is  in  the  treatment  of  the  poor  lead,  in  order  to 
free  it  from  zinc,  the  old  method,  suggested  when  the  zinc  process  was  first  in 
vented,  being  in  use.  The  lead  is  melted  in  a  reverberatory  furnace  under  a 
lnyer  of  coal,  on  which  is  a  layer  composed  of  salt  2  parts,  sand  1  part  and  lime 

1  part.     The  furnace   holds   22,000  pounds  lead,  which  it  is  treated  for  8  to  9 
Lours  and  the  product  is  «'  best  selected"  lead,  the  purity  of  which  is  sufficiently 
proved  by  the  following  analysis  made  at  Clausthalin  1869  : 

Silver ; .  0  0023 

Copper 0  0034 

Antimony 0  0081 

Iron 0-0013 

Lead  by  difference 99-9849 

100 
THE  WORKS  AT  CALL. 

The  works  at  Call3  were  established  tor  the  purpose  of  working  over  old  slag, 
felt  by  the  Koniaus,  or  some  less  ancient  people,  and  this  material  is  still 
treated,  but  the  bulk  of  the  the  lead  is  made  from  purchased  ores.  Tha  latter 
are  obtained  in  Westphalia  and  also  at  Stolberg.  They  are  mixed  with  brown 
spar,  copper  pyrites,  and  zinc  blende  ;  the  lead  contains  about  one-half  per  cent 
of  antimony.  Of  silver  the  lead  contains  about  0-025  per  cent,  or  7 -3  ounces 
per  ton. 

A*  at  Mechernich  the  ore  is  first  roasted  ;  the  furnace  being  45  feet  long  and 
7  feet  wide  with  double  sole,  which  gives  90  feet  of  hearth  length.  This  furnace 
w'll  hold  about  88.000  pounds  of  ore,  which  is  charged  every  6  hours  in  poi-ts  of 
3,300  pounds.  Four  ponts  are  drawn  daily  so  that  13,200  pounds  or  63  tons  are 
roasted  daily.  Like  the  Mechernich  furnaces  there  is  a  deep  hearth  next  the 
tire  place  \\here  the  roasted  ore  is  melted,  and  tBe  furnace"  is  tapped  every  12 
hours.  From  these  figures  it  will  be  seen  that  the  ore  remains  from  6  to  7  days 
in  the  furnace. 

The  blast  furnaces  at  Call  are  remarkable  in  these  days  for  having  but  one 
tuyere.  They  are  19  feet  high,  4  feet  from  front  to  back  aud  3  feet  wide.  The 
top  is  closed  by  a  hopper  built  of  brick  and  lined  with  cement.  This  hopper  is 
large  enough  to  contain  one  charge.  It  is  closed  by  a  slide  which,  being  pulled 
out,  lets  down  the  charge.  The  hearth  is  narrowed  a  little  to  prevent  the  <or- 
niation  of  sows.  About  16|  tons  of  charge  are  smelted  in  24  hours,  i'he  blast 
is  by  fans  and  the  pressure  8  inches  of  water.  Another  furnace  is  square  and 
has  3  tuyeres. 

8.  PreuBB  Zeitechrift,  1868,  p.  288. 


MECHERNICH.  37 

BBPABATION   OF    SILVKB. 

The  lead  which  on  an  average  contains  250  grammes  silver  in  1000  kilograms,  or 
a  little  more  than  7  ounces  to  the  ton,  is  melted  in  kettles  of  7  feet  diameter  aud 
22  inches  depth,  holding  about  25,000  pounds.  The  dross  is  taken  off,  the  lead 
heated  until  zinc  melts  readily  on  it,  when  198  pounds  of  zinc  is  added, 
stirred  for  half  an  hour  and  the  whole  suffered  to  cool  until  the  zinc  solidifies  on 
the  surface,  when  it  is  taken  off.  This  zinc  crust  is  at  first  about  3  hues  thick 
but  the  removal  of  the  surface  lead  is  continued  until  the  lead  begins  to  crystal 
lize  which,  it  has  been  found,  takes  place  when  about  2  inches  of  the  bath  havo 
been  removed. 

The  first  charge  of  zinc  having  been  taken  off  the  kettle  is  filled  up  with 
liquated  lead,  (see  below)  68-2  pounds  of  zinc  are  added,  and  after  a  repetition  of 
the  above  process  a  third  charge  of  38-5  Ibs.  is  put  in.  By  these  three  charges 
304  7  pounds  of  zinc  have  been  added  or  close  on  1J  per  cent,  aud  the  silver  lelt 
in  the  kettle  is  red  need  to  0-00055  per  cent,  or  0-16  of  an  ounce.  The  source  from 
•which  this  liquated  lead  is  obtained  will  be  seen  below. 

The  lead  originally  contained  about  0-15  per  cent,  of  antimony  and  0-2  per 
cent  of  copper.  It  now  has  nearly  all  the  antimony  concentrated  in  the  re 
maining  lead,  but  is  nearly  Iree  from  copper,  which  has  followed  the  silver  in 
uniting  with  the  zinc. 

To  remove  the  zinc  a  method  was  formerly  employed  which  w.is  the  invention 
of  Mr.  HEIJBST,  one  of  the  proprietors  of  the  works.  It  is  to  this  gentleman  that 
metallurgists  owe  the  ro-introductiou  of  the  zinc  process  after  it  had  lain  many 
years  neglected.  His  improvements  and  perseverance  established  the  process 
on  a  successful  basis  lor  the  first  time,  and  the  remarkable  advances  rnnde  in  thi* 
metho/'  during  the  last  ten  years  had  the  following  process  for  a  starting  point, 
though  it  has  siuce  been  abandoned  in  nearly  every  works. 

The  lead  containing  zinc  was  heated  to  a  dark  red  and  covered  with  an  inti 
mate  mixture  of  110  pounds  salt  and  320  pounds  lead  sulphate.  Fur  lead  con 
taining  0-6  percent,  of  zinc,  about  330  pounds  of  th.s  mixture  was  charged  to 
each  kt  ttle.  Soda  sulphate  and  zinc  chloride  were  formed,  but  the  larger  part 
of  the  zinc  must  have  been  removed  as  zinc  oxide.  For  24-750  Ibs.  lead  at  0-6  p. 
c.coutaiu  1485  pounds  of  zinc,  requiring  163  pounds  of  chlorine  to  make  ZuOt. 
But  the  110  pounds  of  salt  charged  contain  only  77  pounds  of  chloriue,  very 
much  of  which  remains  as  sodium  chloride.  The  «•  salt  slag"  remaining  cou- 
biited  of  unaltered  sodium  chloride,  lead  sulphate,  mingled  with  zi.ic  oxychlo- 
ride,  soda  sulphate  and  metallic  let.d.  After  twenty-four  hours  the  zinc  was  all 
removed. 

The  lead  now  contained  no  impurity  but  antimony,  and  it  was  with  a  view  to 
the  removal  of  this  troublesome  in..redient  that  the  peculiar  krttles  used  at  Call 
(and  I  believe  no  where  else)  were  designed. 

Antimony  cannot  be  removed  by  steam,  but  requires  for  its  oz'dation  the  slow 
action  of  air  upon  the  heated  lead.  When  steam  is  used  for  the  removal  of  this 
metal,  as  at  Mechernich  and  many  other  works,  it  acts  merely  as  a  mechanical 
stirrer  of  the  lead,  throwing  it  up  and  changing  its  surface  constantly,  so  that 
every  particle  is  brought  in  contact  with  the  air. 


38  MECHERNICH. 

At  Call  after  poling  the  lead  for  half  an  hour  it  is  kept  a  long  time,  u-ually  48, 
Bometirnes  72  houis  at  a  red  heat,  and  covered  by  a  layer  of  lime  which  prevents 
the  volatilization  of  the  lead,  but  does  not  hinder  the  access  of  the  air.  Lead 
containing  up  to  one  per  cent,  of  antimony  can  be  softened  in  tLis  way  ;  that  at 
Call  sometimes  reaches  one-half  per  c<mt. 

The  complete  removal  of  the  antimony  is  ascertained  by  casting  a  small  ladle- 
ful  of  the  lead  in  a  scorifier  or  assaying  crucible.  So  long  as  this  contracts  in 
cooling  leaving  a  crystalline  star  in  the  centre,  antimony  is  indicated.  But 
when  there  is  merely  a  depression  in  the  centre  of  the  button,  with  no  star,  the 
process  is  known  to  be  finished. 

From  these  operations  results  a  metal  of  great  purity  as  the  following  analysis 
shows : 

Silver , 00005 

Copper ,. 0-OOOt 

Ant  irnony 0  0008 

Iron 0-0019 

Bismuth 0  0023 

Thulium 0-0003 

Lead..  ..99-9938 


100 

EEMOVAL   OF  ZINC  BT   ACID. 

Tbe  innnngemer.t  of  the  zinc  alloy  is  peculiar.  The  ;  Hoy  produced  by  the 
second  and  third  charges  of  zinc  is  kept  separate  from  that  obtained  from  the 
first  addition  of  zinc.  The  former  is  very  much  adulterated  with  lend.  It  is 
melted  in  a  ket'le,  the  alloy  rising  to  the  top,  while  a  "  liquated  lead  "  contain 
ing  about  3-5  ounces  silver  to  thu  ton  remains  under  it.  The  temperature  is 
raised  nearly  to  bright  red,  at  which  the  overlying  layer  oi  alloy  oxuiiz •;*.  When, 
this  oxidation  is  complete,  the  lead  is  drawn  off  by  a  spout,  leaving  the  oxides 
vmn  nearly  all  the  silver  beh  nd.  Tbe  lead  goes  back  to  the  second  and  third 
additions  of  zinc  as  before  said. 

The  oxid-s  are  mixed  with  about  one-half  tveir  weight  of  chlorhydric  acid,  at 
first  in  the  cold  and  afterwards  the  solution  is  completed  at  a  low  heat.  When 
this  operation  is  finished  the  liquid  is  evaporated  until  it  becomes  thick,  a  sign 
that  all  the  water  is  removed.  Then  the  alloy  resulting  from  the  first  charge  of 
zinc  is  Rddfr'd.  In  this  the  lead  und  zinc  are  still  in  the  metallic  state  and  a 
reaction  sets  in  ;  the  zinc  is  all  converted  into  chloride  and  tha  lead  and  silver 
mostly  to  metal.  This  process  takes  24  hours. 

By  this  means  a  rich  lead  containing  1-5  to  2  per  cent,  of  silver  is  obtained 
^rliich  is  cup^li^d.  The  method  has  the  advantage  01  superseding  the  deziucing 
r>f  the  alloy  by  steam,  an  operation  not  free  from  hazard,  and  one  that  .s  always 
H  dis'urbmg  element  in  the  zinc  process. 

The  residue  contains  from  20  to  55  per  cent,  of  lead  chloride,  the  remainder 
hein^  zinc  chloride  with  ]? — 25  ounces  to  the  ton.  We  have  seen  that  the  zino 
in  the  2nd  and  3d  alloys  was  transformed  into  ziuc  chloride  by  treatment  with 
lead  sulphate  and  sodium  chloride  at  a  high  heat  ;  the  result  was  soda  sulphate 


MECHERNICH.  39 

and  zinc  chloride.  Precisely  tho  opposite  reaction  is  now  produced  by  mixing 
these  residues  containing  lead  chloride,  with  "suit  slag  "  obtained  in  do-zincing 
the  poor  lead,  and  treating  them  with  water  acidified  with  chlorhydrio  acid. 

This  acid  changes  the  zinc  oxychloride  to  neutral  ziuc  chloride,  which  is 
soluble.  Copper  chloride  and  silver  chloride  are  also  dissolved,  ihe  latter  in 
consequence  of  the  other  chlorides  in  solution.  But  the  lead  chloride  is  tr<ms- 
f  Trued  to  insoluble  lead  sulphate  by  reaction  with  the  soda  sulphate.  We  havo 
then  the  original  mixture  of  salt  and  lead  sulphate  restored.  After  settling,  the 
liquor  is  ruu  to  a  vat  containing  copper  where  the  silver  ie  deposited,  and  to  an 
other  containing  iron  where  the  copper  falls  down. 

By  these  separations  the  liquor  now  contains  nothing  but  zinc  chloride,  and 
iron  sub-chloride.  The  addition  of  chlorine  transforms  the  latter  to  per-chlorido, 
which  is  precipitated  by  lime.  The  remaining  solution  of  zinc  chloride  is  heated 
and  the  zinc  precipitated  as  oxido  by  pure  lime,  super-saturation,  being  carefully 
avoided.  The  zinc  oxide  is  finally  distilled  to  metallic  zinc. 

This  process  is  an  excellent  example  of  a  simple  method  of  treating  the  rich 
alloy  by  acids,  a  treatment  which  in  m  my  places  is  forbidden  by  the  high  price 
of  chlorhydric  acid.  It  does  not  appear  that  the  acid  is  particularly  cheap  at 
Call,  but  the  small  percentage  of  silver  in  the  lead,  and  the  consequently  small 
amount  ot  alloy  to  be  trcaiecl,  gives  the  acid  meth  >d  advantages  over  the  treat 
ment  by  fusion  with  slag,  or  by  steam.  The  silver  is  obtained  more  quickly 
than  would  be  the  case  if  the  rich  alloy  had  to  be  accumulated  until  enough  was 
at  hand  to  fill  a  kettle,  say  15,0 JO— 20,000  pounds  ;  or  to  support  a  campaign  in 
the  furn.'tce,  which  would  require  even  more.  Thirty  centners  or  6,600  poundg 
Buffices  for  the  treatment  with  acid.  It  is  to  be  remarked,  too,  that  the  shallow 
and  extremely  wide  kettles,  in  use  at  this  place,  may  not  bo  well  adipled  to  the 
use  of  steam  ;  thougb  tint  question  is  still  unanswered,  as  I  believe  steam  has 
not  been  applied  to  kettles  like  them.  Those  recommended  by  COUDUIUE  are 
very  deep  and  of  small  diameter  ;  wliile  those  >n  the  Hirtz  aro  2  leet  104  inches 
deep  and  5  feet  6£  inches  in  diameter,  and  this  is  about  t_ie  siz^  of  the  old 
Pattinsou  kettles  in  most  works,  which  have  been  used  without  alteration  for  the 
ziuc  process. 

But  the  process  described  above  is  no  longer  in  use  at  Call.  Mr.  HKKBST  has 
invented  another  which  he  keeps  secret,  unwilling  to  give  his  disc  >very  gratui 
tous  circulation  and  dissatisfied  with  the  Prussian  patent  laws,  \vhich  he  thinks 
have  not  yiveu  him  protection  enough.  His  new  method  is  said  to  be  chouper 
than  any  other  yet  introduced* 


COLD  AND  SILVER  WORKS  AT  LEND. 


THE  (1)  treatment  of  ores  containing  gold  and  silver,  by  fusion  with  lead  is  one 
of  the  common  operations  of  metallurgists.  A  very  small  establishment  of  this 
kind,  but  in  many  respects  characteristic  of  the  general  European  practice  is 
found  at  Lend,  in  Austria.  This  place  lies  in  the  Salzburg  Alps,  and  receives  its 
ore  from  the  mines  at  Kauris  and  Boeckstein.  The  former  lying  8200  feet  above 
the  sea  is  said  to  be  the  highest  mine  in  Europe,  some  of  its  openings  being 
made  in  glacier  ice.  *  « 

The  ore  differs  in  no  way  but  extreme  poverty  from  countless  mines  in  the 
West.  It  consists  of  gneiss,  quartz,  chlorite  and  clay  slate  ;  containing  iron 
pyrites,  copper  pyrites,  arsenical  pyrites,  galena,  blende,  and  stilbite  or  sulphuret 
of  antimony.  The  gold  is  found  in  two  states  :  free  gold  and  gold  alloyed  with 
silver.  This  alloy,  in  1866  was  composed  on  the  average,  of  15-33  gold  and  84-67 
silver,  which  gives  a  specific  gravity  of  11-28.  Mercury  has  a  specific  gravity  of 
13-6,  and  as  the  amalgamation  of  gold  by  the  Austrian  method,  is  looked  upon  as 
a  proceeding  entirely  mechanical,  the  separation  being  effected  solely  by  the  su 
perior  gravity  of  the  gold  over  mercury  ;  this  alloy  which  is  lighter  than  mer 
cury  cannot  be  amalgamated  (2).  Such  is  the  lesson  of  long  practice,  the  free  or 
fine  gold  beinx  extracted  from  a  part  of  the  ore,  at  least,  by  amalgamation  while 
the  tailings  are  smelted  to  obtain  the  alloy.  The  following  table  will  show  the 
proportion  of  fine  to  alloyed  gold  and  also  exhibit  the  extreme  poverty  of  the  ore. 
To  the  Kauris  and  Boeckstein  ores  are  added  those  from  Zell  in  the  same  part  of 
the  Alps.  The  ore  from  the  last  named  place  is  not  now  worked,  the  point  of 
poverty  having  apparently  been  reached  at  which  the  auriferous  rock  ceases  to 
be  an  ore. 


] 

3 

Fine  Gold 

Kauris                   Boeckstein 
n  2000  Ibs.             In  2000  Ihs. 
"roy  ounces.         Troy  ounces. 
0-32—  0-48              0-098—  0-113 

Zell 
In  2000  Ibs. 
Troy  ounces. 
0-090—0-097 

Auriferous  Silver. 

L4  •  0—H-O              5-700—  6-600 

unimportant. 

Iron  pyrites,   copper  py 
rites,  grtleiia.       

"  8  per  cent.            4£  per  cent. 

unimportant. 

Value  of  Silver  and  Gold  i 
in  American  coin.  .          .  .  ( 

"  $13.49—  $16.92    $5.91—  $8.49 

$1.86  -$2.00 

As  in  1836  Boeckstein  deliveied  63  per  cent,  of  the   ore  smelted  at  the  works 
and  Kauris  37  per  cent.  ;  the  average  value  for  that  year  was  $10-28  or  0-0009 

1.  This  paper  ig  mainly  reprinted  from  one  read  before  the  Institute  of  Mining  En 
gineers  May  22,  1872.    For  the  information  contained  in  i%  I  am  indebted  to  Dr.  LEO 
TUBNEB,  former  director  of  the  works,  now  at  Brixlegg  in  the  Tyrol. 

2.  See  liittinger,  "  Auf  bereilung"  page  4G9  ;  Ed.  1867. 


LEND.  41 

per  cent,  gold  and  0'017  silver.  This  does  not  include  the  value  of  the  copper 
and  lead  which  form  respectively  2  per  cent,  and  1  per  cent,  of  the  ore.  The 
former  is  extracted,  the  latter  is  not  sufficient  to  supply  the  waste  of  the  process 
and  lead  has  to  be  bought  for  the  works.  Even  in  Europe  these  ores  are  con 
sidered  extremely  poor.  1  am  not  aware  that  ores  from  veins  as  poor  as  these 
have  ever  been  utilized  in  this  country,  but  if  they  have  they  owe  their  value  to 
the  fact  that  the  gold  is  all  fine  and  can  be  amalgamated. 

TREATMENT   OF    THE   QBE. 

The  ore  is  first  sorted  to  six  varieties  for  the  furnace  and  one  for  amalgamation. 
The  former  are  quartzose  ore,  rich,  medium  and  poor,  compact  pyrites,  galena 
and  antimonial  ores  (1). 

The  quartzose  ore  consists  mostly  of  quartz  with  which  are  gneiss  and  chlorite  • 
it  contains  iron  pyrites,  arsenical  pyrites,  blende,  copper  pyrites,  and  a  very  littl< 
galena.  Its  value  in  gold  and  silver  is  400 — 2240  grammes  to  the  ton,  or  12  to  7(1 
oz.  Of  this  alloy  from  10  to  30  per  cent,  is  gold.  This  ore  gives  20-25  per  cent, 
of  raw  matte. 

Compact  pyrites  is  composed  of  iron  oxide,  arsenical  pyrites,  and  copper 
pyrites,  and  these  are  often  accompanied  by  magnetite,  when  it  is  usually  richer. 
It  is  nearly  free  from  gangue.  Its  content  varies  between  80  and  400  grammes 
of  gold  and  silver  to  the  ton  ;  or  2-5—12  ounces.  The  gold  forms  about  25  per 
cent,  of  the  alloy 

Glaserz,  is  a  name  given  to  a  mixture  of  quartz  and  gneiss  with  disseminated 
pyrargyrite  ;  silver  and  antimony  sulphide  ;  antimony  glance  and  galena.  Its 
content  varies  very  much,  usually  between  800  and  2000  grammes,  or  26—60 
ounces,  to  the  ton,  of  which  25  per  cent,  is  gold.  Most  of  this  comes  from 
Boeckstein. 

Glance  ore,  or  fine  leaved  galena,  with  4000  or  5000  grammes,  or  140 — 160 
ounces  of  silver,  almost  without  gold,  to  the  ton. 

The  Glaserz  occurs  oftenest  in  quartz  ;  copper  pyrites  and  occasionally  pea 
cock  ore,  in  chlorite  gneiss  ;  blende,  iron  pyrites  and  arsenical  pyrites  in  quartz 
and  gneiss. 

The  mill  slimes  are  of  three  qualities,  ;  1  and  2  are  nearly  pure  pyrites,  having 
been  concentrated  in  milling,  and  giving  50 — 60  per  cent  of  matte.  One  con 
tains  500—1500  grammes  of  alloy,  of  which  7 — 14  per  cent,  is  gold  ;  two  contains 
22 — 75  grammes  alloy  of  which  2*5 — 4  per  cent,  is  gold  ;  three  is  the  poorest 
slime  from  the  shaking  table.  It  gives  25— 30  per  cent,  of  matte,  and  contains 
300 — 1000  grammes  or  10—40  ounces  of  alloy,  of  which  9 — 18  per  cent,  is  gold. 
It  is  used  as  a  siliceous  flux.  Only  the  poorest  ore  containing  merely  traces  of 
pyrites  is  sent  to  amalgamation  ;  which  is  done  because  it  there  undergoes  con 
centration. 

The  ore  for  amalgamation  is  stamped  under  stamps  of  220  pounds  weight  (total) 
through  sieves  of  1.6  mm.  (0-06  inch),  the  stamp  chest  having  a  sieve  on  each 

1  A  full  suite  of  these  orc-s  with  the  furnace  products  at  Lend  can  be  seen  at  the 
School  of  Mines  in  New  York. 


LEND. 


side  to  secure  the  most  rapid  discharge  of  the  slime  possible.  Two  methods  of 
treatment  are  employed  for  the  slimes  :  — 1.  They  are  first  concentrated  and  then 
amalgamated  ;  or,  2.  They  are  first  amalgamated  aad  then  concentrated.  With 


Figure  7.— The  A\istrian  Gold  Mill. 

ore  that  contains  much  pyrites  the  former  is  best  with  ores  very  poor  iu    vrUes, 
the  latter. 


LEND.  43 

Amalgamation  takes  place  in  pans,  there  called  "mills,"  an  illustration  of 
which  is  given  in  figure  7. 

In  this  figure  a  is  the  pan,  I  the  runner,  e  the  arms,  three  in  number,  by  which 
the  runner  is  fastened  to  the  spindle,  s  is  a  brace  which  both  stiffens  the  arm-s  e, 
and  also  transmits  the  movement  of  the  spindle  to  the  arms.  The  spindle  is 
made  square  at  this  point,  and  the  apertare  in  the  brace  being  also  square,  the 
brace,  arms  and  runner  are  carried  round  by  the  revolution  of  the  spindle.  Dis 
charge  takes  place  at  c,  a  spout  of  sheet  iron  d  being  rivetted  to  the  cast-iron 
pan.  The  adjusting  apparatus  consists  of  the  thumb-screw  m.  It  is  to  be  re 
marked  that  the  spindle  ends  at  n,  the  end  being  hollowed  out  to  receive  the  end 
of  the  thumb-screw.  This  screw  works  in  a  thread,  cut  to  receive  it,  in  the  top 
of  the  arms  e.  The  spindle  itself  rests  on  the  beam  p,  and  cannot  move  up  or 
down.  When  the  thumbscrew  m  is  turned,  its  bearing  on  the  top  of  the  spindle 
remains  constant,  but  the  arms  and  consequently  the  runner  are  raised  or 
lowered. 

The  pan  is  made  of  cast-iron,  and  as  it  suffers  little  wear  can  be  made  very 
light.  The  arms,  which,  being  three  in  number,  form  a  tripod,  are  made  of 
light  bar  iron,  of  about  1  k  inches  in  width,  and  4  inch  in  thickness.  The  runner 
is  of  wood,  having  the  shape  of  the  mill,  and  hollowed  out  on  top  so  as  to  form 
a  hopper.  It  is  bolted  to  the  tripod,  bound  with  ordinary  hoop  iron,  and  a 
number  of  short  pieces  of  sheet-iron  are  driven  into  its  lower  sur:ace.  These 
•'  wings"  are  from  2  5  to  3  inches  long  and  4  inch  wide,  and  act  like  the  vanes  in 
a  fan  blower,  or  rotary  pump  ;  that  is,  they  force  the  pulp  to  partake  'of  the  ro 
tary  motion  and  drive  it  out  of  the  machine.  Twenty  to  thirty  wings  are  placed 
radially  in  each  runner,  in  such  a  manner  as  to  break  joints,  from  the  center  to 
the  circumfer-  nee.  Those  which  work  over  the  slanting  part  of  the  pan  are  made 
only  one-half  inch  wide,  in  order  to  allow  the  wings  placed  over  the  mercury, 
freedom  of  motion.  Other  methods  of  gearing  are  also  employed  and  pans  are 
usually  wider  at  the  bottom  than  the  figure  represents.  In  this  pan  the  interior 
of  the  bottom,  where  the  mercury  is  placed,  is  ouly  9  inches  in  diameter  ;  usual 
ly  15  inches  in  the  width.  As  the  center  is  taken  up  by  the  aperture  through 
which  the  spindle  passes,  the  real  width  of  the  annular  space,  filled  with  mer 
cury,  is  in  this  pan  only  3  inches,  and  in  the  ordinary  pan  63  inches.  In  both 
cases  the  diameter  at  the  top  is  24  inches,  height  9  inches  and  the  thickness 
1-3-16  inch. 

When  pulp  is  poured  into  the  runner,  it  passes  through  the  center  opening  or 
eye,  down  to  the  mercury,  where  the  action  of  the  wings  gives  it  a  rotary  motion, 
and  at  the  same  time  carries  it  toward  the  circumference.  These  wings  should 
revolve  just  above  the  mercury,  but  not  in  contact  with  it.  By  this  means,  every 
pai  tide  of  the  pulp  passes  part  or  all  the  way  round  the  pan  before  it  is  discharged, 
and  its  path  over  the  mercury  is  therefore  longer.  It  does  this  with  the  least 
possible  turbulence,  and  the  gold  particles  have  opportunity  to  reach  the  mer 
cury,  where,  sinking  in  that  fluid,  they  are  safe  from  liability  to  be  carried  off  on 
the  stream. 

Successful  work  depends  upon  the  thickness  of  the  pulp  and  the  speed  given 


44  LEND. 

the  runner,  and  one  of  the  advantages  of  this  mill  is  the  readiness  with  which  its 
work  can  de  altered  to  suit  any  kind  or  condition  of  ore. 

Condition  of  the  Pulp.  — This  depends  upon  two  things,  density  and  fineness. 
A  concentrated  ore  has  a  much  higher  specific  gravity  than  undressed  ore,  be 
cause  the  lighter  minerals,  quartz,  etc.,  have  been  removed.  The  difference  be 
tween  its  gravity  and  that  of  gold  is  therefore  less,  and  we  must  take  care,  1st  to 
have  the  slirne  so  thin  that  the  gold  particles  will  have  easy  movement  through 
it ;  and  2nd  that  the  motion  of  the  runner  shall  be  fast  enough  to  keep  the  heavy 
material  which  it  has  to  carry  along,  from  settling  on  the  surface  of  the  mercury. 
Experience  has  proved  that  with  undressed  ore  containing  not  more  than  10  per 
cent,  of  heavy  mineral  (pyrites,  etc.,)  to  90  per  cent,  of  gangue,  the  runner  should 
make  from  12  to  15  revolutions  per  minute  ;  from  one-half  to  one  cubic  foot  of 
pulp  may  be  passed  every  minute  ;  and  finally  this  pulp  must  be  of  such  a  thick 
ness  that  not  more  than  125  pounds  of  ore  shall  pass  through  the  the  mill  in  one 
hour. 

When  the  ore  has  been  concentrated  the  conditions  are  quite  different.  The 
runner  is  revolved  at  the  rate  of  20  to  30  times  a  minute,  and  the  pulp  must  be 
thinned  so  that  not  more  than  13  to  15  pounds  of  ore  pass  through  the  mill  hour 
ly.  The  amount  of  pulp  however  must  be  kept  up  to  a  half  or  one  cubic  foot  a 
minute. 

If  the  pulp  is  too  coarse  it  hangs  back  in  the  mill  and  chokes  it,  if  it  is  too  fine 
the  gold  does  not  settle.  Good  stamp  work  answers  well.  It  is  not  well  to 
suffer  pulp  to  dry  and  then  wet  it  to  run  through  the  mill.  Experience  proves 
that  the  extraction  is  not  so  good  under  such  circumstances,  probably  because 
the  particles  of  gold  have  air  adhering  to  them  which  lessens  their  gravity. 

Two  or  three  mills  are  usually  placed  one  after  the  other.  With  these,  of  the 
whole  amount  of  gold  extracted  from  a  pulp  rich  in  galena  and  therefore  not 
favorable  to  amalgamation. 

The  first  extracted 65  per  cent. 

The  second 25        " 

The  third 10 

With  a  sandv  pulp  which  contained  little  heavy  mineral  the  result  was  : 

The  first  extracted 74  per  cent. 

The  second 20         " 

The  third .., 6        " 

One  mill,  or  one  set  of  2  or  3  mills,  will  pass  from  2,250  to  3,000  pounds  of 
undressed  pulp  in  24  hours.  Of  dressed  ore  it  will  pass  through  about  as  much 
as  would  correspond  to  that  quantity  of  unconcentrated  pulp.  When  the  ore 
contains  10  per  cent,  of  heavy  minerals  there  is  no  gain  in  previous  concentration, 
while  the  extraction  is  better  with  undressed  pulp. 

In  this  apparatus  loss  of  mercury  is  reduced  to  a  minimum.  With  two  rows 
of  pans  the  loss  for  100,000  pounds  of 

pulp  rich  in  heavy  mineral  was 1-5  to  2  pounds 

"poor  "  "         "  1  to  1-5  pounds 

In  the  first  case  it  was  therefore  about  one-half  ounce  to  one  ton ;  in  the  second 
one-third  ounces.  Clayey  ores  and  those  containing  antimony  increase  this  loss. 


LEND.  45 

The  yield  can  be  increased  by  concentrating  the  amalgamated  pulp,  and  re- 
passing  the  tailings  under  the  conditions  necessary  in  working  concentrated 
pulp.  By  this  means  from  20  to  30  per  cent,  of  the  lost  mercury  is  recovered, 
while  about  the  same  amount  of  the  ainalgamable  gold  is  also  won.  The  first 
operation  extracts  about  70  per  cent. 

The  power  necessary  to  run  one  mill  is  about  one  twenty-fith  of  a  horse  power. 
A  twelve  pan  apparatus  costs  in  Austria  about  $250. 

Compared  with  the  Colorado  methods,  these  mills  extract  20  per  cent,  more 
than  the  Colorado  amalgators,  though  this  yield  necessarily  depends  upon  the 
per  centage  of  silver  in  the  native  gold.  They  require  little  watching,  except 
when  used  immediately  after  the  stamps,  when  the  accumulation  of  gold  might 
necessitate  cleaning  up  every  two  or  three  days. 

Smelting.— For  four  years  the  ores  delivered  for  fusion  were  in  the  following 
proportions  : — 

From  Kauris.  From  Boeckstein. 

Quartzose  ore 6.50  24.11 

Compact  pyrites 0.06  0.48 

Sulphuret  of  Antimony 1.41  0.41 

Slime  from  Amalgamation 29. 03  38. 00 

37.00  63.00 

About  60  per  cent,  of  the  ore  has  therefore  been  amalgamated.  As  this  was  done 
because  the  ore  was  too  poor  to  smelt  we  may  gain  an  idea  of  the  extreme  pover 
ty  of  the  original  ore. 

From  the  table  of  valuos  before  given,  it  is  evident  that  70—75  per  cent,  of  the 
ore  is  worthless  rock,  and  this  must  ba  removed  before  adding  lead,  which  would 
suffer  serious  loss  if  charged  with  so  mujh  quartz.  The  operations  are  therefore 
as  follows  :— 

1.  Fusion  for  raw  matte. 

2.  Boasting  of  raw  matte  in  stalls. 

3.  Fusion  (without  lead)  for  a  more  concentrated  matte. 

4.  Roasting  of  2nd  matte  in  stalls. 

5.  Fusion  with  lead. 

6.  Cupellation  of  rich  lead. 

The  First  Faxion.— Eleven  years  experience  has  proved  that  the  most  efficient 
slag  is  one  approaching  the  composition  of  a  bisilicate.  The  followiug  is  an 
analysis  of  an  average  slag  from  the  first  fusion  : — 

Silica 51.02 

Alumina 2. 16 

Oxide  of  Iron ....  19. 75 

Lime 15.40 

Magnesia 8.57 

As.  Mn.  Ca 

Zn.  S.  bydif. 3.10 


100,000 

The  furnace  is  not  new  and  contains  none  of  the  late  improvements  ;  but  it 
does  good  s  rvice.     Its  general  dimensions  are  as  follows  : — 


LEND. 

Height 24=  feet. 

Diameter  of  hearth 3     " 

' '  boshes 4     " 

throat 2     " 

Number  of  tuyeres 2     " 

Pressure  of  blast i — £  in.  of  mercury. 

From  100  to  120  bushels  of  charcoal  are  required  to  warm  the  furnace,  and 
then  regular  charges  of  5  cubic  feet,  or  about  3  bushels  are  thrown  in.  In  blow 
ing  in,  the  quantity  of  mixed  ore  and  flux  added  to  this  quantity  of  charcoal  is,  at 
first  56  pounds,  then  112  pounds,  and  finally  when  the  furnace  is  thoroughly  hot, 
203  pounds,  which  is  the  constant  burden  of  mine  to  three  bushels  of  charcoal. 
This  is  usually  reached  in  the  first  24  hours.  Four  hours  after  the  first  charge 
of  ore  and  flux  the  blast  is  turned  on,  at  first  with  a  pressure  of  i  in.,  and  then  £ 
in.  mercury  ;  or  one-sixth  and  one-quarter  pounds  pressure.  After  eight  hours 
the  slag  begins  to  flow.  The  furnace  is  worked  with  a  black  throat.  The 
labor  per  ton  of  ore  and  flux  amounts  to  1.8  days. 

Ihe  First  Matte,  forms  40  to  45  per  cent,  of  the  charge,  the  difference  between 
this  proportion  and  the  20  to  30  per  cent,  afforded  by  the  ore  being  made  up  by 
roasted  matte  which  forms  a  part  of  the  charge.  Its  average  composition  is  : — 

Iron 55.1 

Copper 4.3 

Zinc 3. 7 

Lead 2.1 

Nickel,  Cobalt,  Arsenic  and  Antimony. . .    .      45 

Sulphur 27.9 

976 

It  contains  30  to  40  ounces  Troy  of  auriferous  silver  to  2,000  pounds  ;  or  in 
American  valuation  $100  to  $150  in  coin.  From  the  fact  that  the  ore  is  un- 
roasted,  and  the  metals  are  therefore  so  well  "covered"  by  sulphur,  the  loss  in 
this  opoi  ation  amounts  to  only  one-quarter  of  one  per  cent.  About  38  bushels 
of  charcoal  are  used  to  the  ton  of  charge,  and  9. 75  tons  are  smelted  in  z4  hours. 

The  Second  Fusion. — The  first  matte  is  roasted  three  times  in  stalls  containing 
28  tons,  the  roasting  not  being  thorough,  but  carried  only  so  far  as  to  leave  about 
40  per  cent,  of  unroasted  matte.  It  is  then  resmelted  with  quartz,  and  to  avoid 
the  use  of  too  much  of  the  latter,  a  basic  slag  is  made  containing  about  22  per 
cent,  silica.  This  requires  very  great  care  in  managing  the  furnace,  for  the  least 
irregularity  will  cause  the  formation  of  sov/s.  To  secure  proper  working,  when 
ever  the  furnace  is  tapped,  the  hearth  is  exaurned  by  means  of  a  bent  bar.  If 
lumps  are  felt  the  front  wall  is  broken  out,  and  they  are  removed  ;  if  Ihe  sole  is 
slippery  the  presence  of  reduced  iron  is  indicated.  A  rough,  hard,  even  sole,  is 
the  proper  one 

The  pressure  of  blast  is  now  reduced  to  one-sixth  of  an  inch  or  one-twelth  of  a 
pound  to  the  square  inch  ;  the  hearth  is  10  to  12  inches  larger  in  diameter  than 
before,  and  the  charge  is  increased  to  222  pounds  to  3  bxishels  of  charcoal. 
These  changes  have  for  their  object  not  only  the  prevention  of  iron  sows  but  also 
of  speise,  a  compound  of  arsenic  with  all  the  other  me'als,  very  difficult  to  utilize. 


LEND.  41 

Speise  is  lighter  than  matte,  aud  in  the  basin  lies  next  above  it.  That  at  Lend 
contains  a  great  deal  of  gold,  and  experiments  made  a  few  years  ago  to  recover 
this  inet.il  by  roasting  and  fusion  with  lead  were  not  successful,  though  the  speise 
was  roasted  iu  8  to  12  fires  and  smelted  with  twice  its  weight  of  lead.  It  was  found 
nearly  impossible  to  oxidize  all  the  speise  and  the  unroasted  part  retained  its 
gold  with  stubbornness.  The  same  precautions  are  used  in  blowing  in  as  before. 
About  30  bushels  of  charcoal  are  used  to  the  ton  of  ore  and  flux,  and  13.5  tons 
are  fused  in  24  hours.  The  second  matte,  contains  50  to  GJ  ounces  of  auriferous 
silver  to  2,000  pounds,  worth  about  $200. 

Fusion  with  Lead.  —The  second  matte  is  roasted  as  before,  but  now  50  to  60  per 
cent,  of  raw  matte  is  left  A  stronger  roasting  would  so  enrich  it  that  two 
fusions  with  lead  instead  of  one,  would  be  necessary.  The  slag  is  again  basic 
and,  to  keep  the  heat  as  low  as  possible,  the  pressure  of  blast  is  reduced  to  one 
and  one-half  hues  of  mercury,  while  the  charge  is  increased  to  277  pounds  of 
matte  and  flux  to  3  bushels  of  charcoal.  In  order  to  keep  the  lead  in  contact 
with  the  matte  as  long  as  possible,  as  well  MS  to  decrease  the  heat,  the  crucible  is 
made  a  foot  deeper  than  before.  The  new  slag  has  au  average  composition  of 

Silica...    27.45 

Oxide  of  Iron 56. 52 

Lime 10.19 

Magnesia 3.48 

Alumina 1.25 

The  loss  will  not  exceed  2. 5  per  cent,  of  the  lead.  When  the  hearth  is  full  of 
melted  matte  and  lead,  it  is  tapped,  the  products  running  into  a  basin  where  they 
are  well  stirred  with  poles.  The  matte  is  then  partially  taken  off,  the  lead  re 
maining  until  60i>  to  700  pounds  has  collected. 

For  a  perfect  extraction  of  the  silver,  it  is  necessary  to  charge  120  to  130 
pounds  of  lead  for  each  pound  of  silver  and  gold,  and  the  matte  must  not  con 
tain  more  than  20  per  cent,  copper.  With  this  proportion,  75  per  cent,  of  the 
silver  and  gold  are  extracted  in  one  operation,  and  the  matte  ought  not  to  con 
tain  more  than  0.75  per  cent,  of  lead.  The  extraction  of  75  per  cent,  of  aurifer 
ous  silver,  means  that  90  per  cent,  of  the  gold  and  73  per  cent,  of  the  silver  has 
been  obtxined.  The  absolute  loss  of  these  metals  is  but  0.10  of  one  per  cent. 
From  14  to  16  tons  are  smelted  in  24  hours.  A  certain  amount  of  lead  matte  is 
obtained  which  is  charged  back  in  the  same  operation.  Of  charcoal,  28  bushels 
to  the  ton  are  used.  If  the  matte  is  rich  enough,  it  now  undergoes  a  repetition 
of  this  operation,  but  usually  it  is  so  poor  that  it  is  treated  immediately  for  cop 
per.  If,  however,  it  contains  less  than  35  per  cent,  of  copper,  it  is  roasted  and 
charged  as  a  flux,  in  the  first  operation  for  raw  matte.  At  Lend  the  conditions 
are  such  that  this  takes  place  every  other  year,  copper  being  made  one  year  and 
matte  the  next.  The  labor  amounts  to  0.46  days  per  ton  of  matte  and  flux,  and 
the  loss  of  lead  is  about  18  pounds  to  the  ton  of  matte. 

Oiipellation  is  performed  in  a  German  furnace  with  a  moveable  hood,  made  very 
low.  Inasmuch  as  none  of  the  side  products  are  sold,  and  there  is  no  need  of 
having  them  in  great  purity,  there  is  beside  the  fire  bridge,  but  one  opening  in 
the  hearth,  through  which  abzug,  abstrich,  litharge  and  smoke  all  escape.  From 


48  LEND. 

6,000  to  7,000  pounds  of  lead  are  first  charged,  and  more  is  gradually  added  until 
about  21,000  pounds  (or  the  entire  make  for  the  year)  has  been  melted.  The 
bkst  is  slow,  and  the  litharge  consequently  flows  rather  cold.  Kenning  fallows 
the  brightening  of  the  silver,  and  metal  of  985  fineness  is  produced.  Usually 
the  loss  of  lead  falls  between  5  and  6  per  cent.,  while  that  of  silver  and  gold 
seldom  reaches  0. 10  per  cent.  About  3  tons  are  cupelled  in  24  hours,  and  the 
labor  is  0.24  days  per  ton. 

TABLES  OF  THE  OPERATIONS. 

The  following  tables  will  give  at  a  glance  all  the  foregoing  particulars.  The 
first  two  operations  are  combined  in  one  table,  and  instead  of  calculating  the  ex 
pense  of  charcoal  upon  the  quantity  of  material  treated  in  each  operation,  that 
and  the  amount  of  labor  will  be  calculated  upon  the  ton  of  ore.  This  is  done  in 
order  to  ascertain  how  much  labor  and  fuel  are  necessary  to  treat  a  ton  of  ore  by 
the  Lend  process.  The  amount  of  ore  is  taken  at  109  tons  since  there  was  21 
tons  of  matte  remaining  from  the  previous  year  which  was  smelted  with  the  ore. 

TABLE    OF   THE    1ST   AND    2ND   FUSIONS,    1866. 

Weight  Ounces  Ounces           p.  c.  of 

Uiarge                                      Tons.  of  Gold.  of  Silver.        Copper. 

Ore       81-15  21-0094  1333-4052 

Matte  and  Kich  Scraps 89 "61  19-2918  2216-6406 

„.          j  Basic  7.41 ,-G  2q 

Flux     1  Siliceous  50.88  .  . .  59  29 


Total  229-05  40-3012          3550-0464 

Produces. 

First  Matte 61-38  18-7193  1612-7324          5 

Second  Matte 30-87  20-4769  1806-7302        10 

Scraps 10-25  -6824               95HJ922 

Total 39.8776  3514-5548 

Labor  39  twelve  hour  shifts  ;  5  men  to  each  shift  — 195  days. 
Charcoal  for  warming  furnace,  291  bushels, 
for  smelting,  6,820 

7,111 

Charcoal  per  ton  of  ore 65-2  bushels 

Labor  per  ton  of  ore 1.8  days. 


LEND. 


49 


TABLE  OF  THIED  FUSION,  1866. 


Tons. 


Rich  quartzose  ore ...    1  -96 
Roasted  2d  Matte. . . .  30-87 
(Scraps 2-09 


Lead. 
Pounds. 


Copper. 
Per  ct. 


10 


Gold. 

Troy 
ounces. 

0-9610 

20-4769 

•1474 


Silver. 
Troy 
ounces. 
59-5404 
1806-7202 
23-0778 


Lead  Matte 3-71  741              6        1  -9440 

J  Litharge     10-81  17,722 

|  Hearth 3-30  3,304 

t 

j  Slag  from  1st  Fusion.  ..10-99 
'  1  Quartz 2-04 


66-77 
Products. 

Lead ! -. . . .  10-51          21,030 

Third  Matte 15-59 

Lead  Matte 3-70  741  20 

Scraps  and  Flue  Dust 4-06  10 


21-5442 

1-9440 
0-2430 


175  9600 
66-1500 
42-4700 


23-5293        21 75 '9184 


.1283 '8320 

624-5200 

174-9600 

46-9900 


237312      2130.2920 


Labor  10  twelve  hour  shifts  ;  5  men  in  each — 50  days. 

Charcoal  for  warming  the  furnace 100  bushels. 

"       "    smelting 1710         «• 

1810        « 

Labor  per  ton  of  ore 0-46  days. 

Charcoal         "  16-6  bushels. 

Lead  charged  " 218  pounds. 

TABI^E  OF   CUPKLLATION. 

Gold.  Silver. 

Charged.                                Tons.       Lead  p.  c.  Troy  ounces.         Troy  ounces. 

Lead 10.06              100  21-5442                1283-8320 

Products. 

Fine  Silver 1208 -58  oz.  21-5294               13869560 

Litharge 10  tons               82  64-9080 

Hearth 253"                 50  31-9860 

Loss 0-0144 

Gain 0. 1800 

Labor,  26  days  =  per  ton  of  ore 0.24  days. 

Wood,  7-52  cords.         "  0-69  cords. 

Charcoal,  40-00  bushels  =  per  ton  of  ore 0-37  bushels. 


LEND. 


TABLE  OF  COST  PEE  TON  OP  OKE  IN  UNITS  OF  LABOR  AND  MATERIAL. 


Labor. 
Days. 

First  and  Second  Fusion 1.8 

Third  Fusion 0<46 

Cupellation 0-24 


Charcoal. 

Bushels. 
65-2 
16-6 
0-37 


Wood. 
Cords. 

0-69 


Lead. 
Pds. 

8-0 
9.7 


Total 2-50  82-17  0-69  17-7 

To  this  must  be  added  a  small  quantity  of  wood  or  refuse  charcoal,  used  in 
roasting  the  matte.  Some  discrepancies  will  be  noticed  between  the  expense  of 
charcoal  as  given  in  these  tables  and  that  allotted  to  each  operation  in  the  text 
This  arises  irom  the  fact  that  the  latter  is  calculated  upon  the  proportions  of 
flux  and  ore,  while  the  tables  are  calculated  upon  the  ore  alone.  They  are  also 
more  complete  :  including  fuel,  for  blowing  in,  blowing  out,  and  any  extra  sup 
plies  needed  in  particular  states  of  the  furnace.  The  quantity  of  charcoal  has 
been  calculated  on  the  heaped  bushel  of  2,748  cubic  inches.  The  above  cost  is 
for  ores  of  the  richness  before  given .  With  richer  ores  there  is  more  matte  to 
treat  and  lead  lost,  and  the  cost  is  therefore  somewhat  greater  per  ton  ;  but  it  is 
proportionately  less  per  pound  of  gold  and  silver.  The  following  table  gives  the 
relative  cost  for  various  ores  ;  the  cost  of  the  poorest  being  taken  as  unity  :— 

Auriferous  Silver  Value  in  American  Proportionate  Cost ;  lowest 

in  2000  Lbs.  Coin.  taken  as  Unity. 

0—  14-5.  oz.  $    0-$  61  1 

14-5—  29-0  $  61— $122 

29-0—  58-0  $122- $244 

58 -0-1 16-0  $244- $488 

The  Lend  ore  falls  under  the  first  kind  ;  the  milling  ore  of  Colorado  is  worth 
from  $20  to  $30  a  ton,  arid  therefore  is  also  in  the  lowest  section  ;  the  ' '  smelting 
ore,"  so  called,  would  be  mostly  in  the  2nd  and  3d  ranks. 

LOSSES.— By  reference  to  the  above  tables  it  will  be  found  that  the  following  is 
the  loss  and  gain  of  the  year. 


MO 
1  31 
1-73 


First  and  Second  Fusions  
Third  Fusion  

G 
oz. 

4-24 

0  15 

1 

Did. 

p.  c. 

jOSS. 

Silver. 
oz.    rp.  c. 

Gol< 
oz. 

2-029 
2-029 

GA 
1. 

p.  c. 

0.86 

IN. 

Si 
oz. 

0-02 
0-02 

iver. 
p.  c. 

0-0015 

1 

0.07 

35-50 
4563 

2-8 
3-6 

Cupellation                             •    •  •  • 

Total  loss.  .  . 

4-39 
2-36 

1-1 

81-13 
81-11 

6-2 

Dr.  Turner's  opinion  founded  upon  years  of  experience,  is  that  more  than  90 
per  cent,  of  the  silver  and  96  per  cent,  of  the  gold  can  be  counted  upon  in  the 
two  processes  of  amalgamation  and  fusion.  Some  years  ago  he  undertook  to  ascer 
tain  the  loss  incurred  in  amalgamating  and  found  it  to  be  45  per  cent  He 
therefore  placed  no  reliance  upon  his  results,  but  when  we  consider  the  poverty 
of  the  milling  ore,  we  shall  see  that  a  loss  of  one  half  the  gold  contained  in  it 
would  affect  but  very  little  the  grand  result 


LEND.  51 

The  cost  of  all  the  operations  in  1866,  at  Lend,  was  $883.88,  and  the  balance 
sheet  shows  a  profit  of  $1,355.  The  expense  was  proportioned  as  follows  :  Labor 
17,  materials  43,  direction  40  ;  total  100. 

At  th'ese  works  all  avoidable  causes  of  loss  have  been  eliminated,  or  their  opera 
tion  recluced  with  the  greatest  care.  Two  analyses  a  year  determine  the  propor 
tions  of  the  charges  and  the  composition  of  the  slag.  Larger  works  would  re  * 
quire  more,  but  there  is  no  reason  why  the  largest  works  should  not  be  conducted 
with  equal  care. 

Great  care  is  necessary  on  account  of  the  extremely  small  quantity  of  ore  smelted  ; 
—only  83  tons  in  1866,  worth  less  than  $2260  in  gold  and  silver,  but  furnishing 
also  a  ton  and  a  half  of  copper.  But  to  treat  this  small  quantity  an  engine'  r, 
and  two  smelters  and  four  assistants  have  to  be  supported  all  the  year  through, 
though  they  work  only  27  days  of  24  hours.  Of  course  such  a  state  of  things  ca,u 
be  maintained  only  by  low  prices,  and  we  find  the  Austrian  workmen  paid  at 
rates  varying  from  27£  to  22  cents  (coin)  a  day.  Charcoal  is  3  1-7  cents  a  bushel, 
and  wood  $1  17  a  cord.  In  this  country  we  should  have  larger  supplies  of  ore, 
sufficient  to  carry  on  the  largest  works  on  a  correspondingly  economical  scale. 
The  nature  and  higher  value  of  our  ores,  too,  would  enable  us  to  work  with  less 
expense  of  labor  and  material  to  the  Troy  pound  of  gold  and  silver  than  at  Lend. 
In  considering  these  results  for  guidance  in  using  a  similar  process  at  the 
"West  it  is  evident  that  the  American  ores  contain  nothing  to  prevent  the  applica 
tion  of  this  process.  Antimony  and  arsenic  and  zinc,  the  bugbears  of  the  smelter, 
are,  with  the  exception  perhaps  of  zinc,  quite  as  prevalent  at  Lend  as  in  Colorado, 
Our  ores,  too,  contain  more  pyrites  than  those  we  have  been  considering  and 
there  would  be  no  necessity  for  a  fusion  for  raw  matte.  Whether  there  ought  to 
be  a  fusion  for  concentration  depends  upon  the  richness  of  the  ore,  and  its 
adaptability  to  concentration  by  machinery.  A  mixture  of  rich  "smelting  ore' 
and  concentrated  tailings,  such  as  is  now  worked  up  by  the  smelters,  could  be 
roasted  and  immediately  fused  with  lead.  One  more  fusion  with  a  fresh  quantity 
of  lead  and  cupellation  would  complete  the  process.  We  should  then  have  a  pro 
cess  divided  as  follows : 

1.  Cupellation  of  poor  ore. 

2.  Boasting  of  concentrated  and  rich  ore. 

3.  Fusion  of  roasted  ore  with  lead. 

4.  Roasting  of  matte. 

5.  Fusion  of  matte  with  lead. 

6.  Cupellation, 

As  to  the  cost  of  a  process  like  this,  we  have  the  following  details.  A  ton  of 
concentrated  tailings  is  produced  in  Colorado  at  an  average  cost  of  $6.  The  ex 
penses  for  the  other  5  operations  would  be  : 

Day's  labor.  Charcoal.  Wood. 

Roasting  in  Piles  0-4  0-029  cords. 

1st  and  2nd  Fusions  1-8  65-2 

Roasting  m  atte  0  -2  0  -004 

Third  Fusion  0-46  16-6 

Cupellation  0-24  00-37  0-69 

10  82-17  0-720 


62  LEND. 

Mr.  Hagne  says  that  the  millers  expect  to  get  one  ton  of  concentrated  tailing* 
from  six  tons  of  ore.  At  that  basis  the  theoretical  expense  would  be  : 

Concentrating  6  tons  to  one $  6  00 

Smelting  1  ton,  3-10  days  labor  @  $3 9  30 

Smelting  1  ton,  82  -17  bushels  charcoal  @  25c 20  54 

Smelting  0'72  cords  wood  @  $8 6  00  . 

Treatment  of  6  tons  milling  ore 41  84 

Mining  of  6  tons  milling  ore  @  $10 60  00 

Total  cost  of  treatment 101  84 

Cost  of  one  ton 16  94 

The  expense  of  charcoal  ought  to  be  somewhat  less  than  this,  for  in  conse 
quence  of  the  small  quantity  of  material  treated  at  Lend  no  less  than  2.5  bushels 
of  coal  to  a  ton  of  ore  are  expended  in  heating  the  furnace.  If  we  add  one  half 
more  for  loss  in  blowing  out  we  have  the  very  large  proportion  of  3. 7  bushels,  a 
quantity  that  would  be  lessened  one  bushel  if  330  tons  of  ore  were  smelted  at 
each  campaign.  With  proper  management  this  could  be  very  much  exceed  d  so 
that  the  expense  of  charcoal  for  blowing  in  and  blowing  out,  would  be  too  small 
per  ton  to  be  worth  reckoning. 

It  now  remains  to  consider  the  adaptability  of  this  process  to  western  ores,  and 
I  will  take  those  of  Colorado  as  an  example,  for  the  reason  that  Mr.  Hague's  re 
port  on  mines  of  that  Territory  offers  the  best  data  for  calculation.  He  gives 
commercial  assays  of  the  ore  from  various  lodes  which  prove  the  average  value  of 
the  ores  to  be  as  follows  : 

First  class  ore  :  Gold.  Silver. 

Consolidated  Gregory 5. 6  oz.  20  oz. 

Illinois 4  20 

Gardner 3.5  11.5 

California .3.  18 

Burroughs 6.  12 

Average 4.42  16.3 

Milling  ore  : 

Burroughs  (1340  tons) 1  oz.  4.5  oz. 

The  value  of  the  first  class  ore  is  $91.36  for  the  gold  and  $21.03  for  the  silver  ; 
total  $112.13.  Let  us  see  what  manipulation  it  requires  :  Boasting  the  ore  so  us 
to  leave  33  per  cent  raw  matte,  and  smelting  with  180  to  195  pounds  of  lead  to  the 
ton  of  ore  we  ought  to  extract  in  one  operation  93  per  cent  of  the  gold,  or  4. 05 
ounces  worth  $83.71  ;  and  73  per  cent,  of  the  silver  or  11.90  ounces  worth  $15.- 
35  ;  total  yield  $99. 05.  (4)  The  expense  of  working  would  be  as  follows  : 

(4)  By  reference  to  the  tables  of  cupellation  audioes  it  will  be  seen  that,  in  1866  more 
than  99  per  cent,  of  the  gold  was  obtained  by  one  fusion  with  lead  ;  while  of  the  silver 
60  per  cent,  was  obtained  as  metal,  and  32  per  cent,  was  retained  by  the  third  matte 
and  went  under  treatment  the  following  year,  2A  per  cent,  was  contained  in  the  scraps 
and  flue  dust,  3.3  per  cent,  was  retained  by  the  litharge.  The  latter  two  should  be 
ueglected  for  they  are  constant  from  year  to  year,  and  the  real  percentage  yield  was  iu 
1866,  therefore,  63-8  per  cent,  fine  silver,  and  33- 9  per  cent,  silver  in  the  matte. 


LEND.  53 

Mining— 1  ton $10  00 

Koasting— 0.4  days  labor  @  $3 $1  2J 

0.029  cords  wood  @  $8 0  23 

8  mos.  int.  011  $10  @  12  p.  c.        80  2  23 

Smelting— 1 .5  days  labor  @  $3 4  50 

8  pounds  lead  (&  5c 40 

46  bushels  charcoal  @  25c. . .  11  50          16  40          18  63 


Total  for  mining  and  smelting. .  .  28  63 

,  If  our  ore  contains  no  copper  the  matte  will  not  pay  for  further  treatment 
and  we  proceed  at  once  to  cupella  ion,  for  which  we  have  in  addition  : 

Cupellation  :  0. 24  days  labor  at  $3 $0  75 

0.37  bushels  coal  at  25c 09 

0.69  cords  wood  at  $8 5  52 

9  Ibs  of  lead  at  5c 45  681 

Add  mining  and  smeltiug 28  63 

$35  44 
Profit:   $99  06— $35  44=363  62. 

"We  have  remaining  a  matte  containing  $7  48.  Let  us  see  whether  this  will 
pay  to  work  by  itself.  The  expense  will  be  for  Colorado  rather  greater  than  for 
Lend  because  the  proportion  of  pyrites  in  the  ore  is  greater.  Assuming  this 
excess  equal  to  50  per  cent,  and  increasing  each  item  to  that  extent  we  have  : 

Boasting  :    0.50  days  labor  at  $3 $0  90 

0.2  cords  wood  at  $8 18       1  08 

Smelting:  0.60  days  labor  at  $3 .....     180 

27  bushels  of  coal  at  25c 6  75 

5  pounds  lead  at  5c 25        9  80 


Total $10  88 

This  would  leave  a  loss  ;  $7  48— $10  88=mmus  $3  40.  The  loss  by  direct 
treatment  would  therefore  be  $3  40.  This  matte  however  could  be  returned  to 
the  first  fusion  again  and  again,  until  the  copper  which  is  present  to  some  extent 
in  almost  all  the  ores  were  concentrated  sufficiently  to  give  the  matte  a  value  for 
its  copper.  With  ores  containing  much  copper  the  matte  might  be  immediately 
saleable,  and  both  silver  and  copper  bring  their  value.  At  present  however,  and 
especially  with  milling  ores,  the  process  would  probably  consist  of  three  stages, 
as  follows  : 

1.  BOASTING. 

2.  FUSION  WITH  LEAD. 

3.  CUPELLATION. 

To  illustrate  the  working  of  the  process  with  milling  ore,  let  us  take  the  Bur 
roughs  ore  as  a  specimen.  It  is  worth  one  ounce  gold,  or  $20  67,  and  4  5  oz. 
silver,  or  $5  80  ;  total  $26  47-  This  is  an  average  yield,  as  most  of  the  milling 
ore  of  Colorado,  so  far  treated,  lies  between  $18  and  $35  in  value.  We  have  foi 
its  treatment  by  fusion  the  following  expeases  : 


FREIBERG. 


ALTHOUGH  the  processes  in  use  at  Freiberg  have  been  described  with  tolerable 
frequency,  few  persons  who  are  not  instructed  in  schools  of  mines,  have  a  just 
appreciation  of  the  works  there,  or  a  correct  idea  of  the  methods  in  use.  Those 
methods,  in  fact,  change  so  constantly  that  it  would  require  a  year-book  to  keep 
pace  with  them.  They  have  changed  so  much  since  1870,  that  in  writ'ng  the 
following  description,  the  work  ot  later  travellers,  such  as  Messrs.  KAST,  BUAUN- 
INO  and  KUHLEMANN,  all  of  them  connected  with  the  great  works  in  the  Hartz 
Mountains,  and  BALLING,  of  the  Austrian  service,  have  been  freely  drawn  upon. 

After  more  than  500  years'  exploitation,  the  mines  of  Freiberg  form  a  vast  net 
work  of  galleries  and  drifts.  Within  the  century  ending  in  1865  a  total  length  of 
25  German  miles,  or  115  English  miles  of  passages  was  excavated,  and  the  mines 
were  deepened  700 — 900  feet.  What  the  cubic  contents  amounted  to  is  not  known, 
but  it  is  surmised  from  the  number  of  men  employed  in  1765,  (1255,  of  whom 
probably  not  more  than  600  were  engaged  in  breaking  down),  that  about -19,200 
cubic  yards  or  5,539  cords,  of  128  cubic  feet,  of  rock  was  taken  out  in  that  year. 
The  amount  excavated  in  1865  was  128,206  cubic  yards  or  59,190  cords,  which 
gives  close  on  8  cords  per  (Jerman  Lachter  (6  2-3  feet)  of  exeavatiou.  At  the 
same  rate  the  excavation  for  100  years  past  would  average  36,969  cords  per  year. 
It  is  a  matter  of  interest  to  know  that  in  1765  a  cord  of  rock  gave  1  ton  of  concen 
trated  ore  ;  while  in  1865  a  cord  of  rock  gave  only  66-100ths  of  a  ton.  Baron 
VON  BEUST,  however,  does  not  ascribe  this  falling  off  to  a  regular  decrease  of  the 
ore  in  depth,  nor  to  the  fact  that  the  dressing  works  now  accept  poorer  ores 
from  the  miner  than  then,  though  this  probably  has  some  effect ;  but  rather  to 
the  very  large  works  for  drainage  and  improvement  of  communication,  most  of 
which  are  done  in  dead  rock,  outside  of  the  veins,  and  (chiefly)  to  the  fact,  of 
which  he  is  persuaded,  that  the  Freiberg  mines  now  and  for  some  years  back, 
have  been  worked  in  one  of  those  zones  of  medium  and  poor  ore  which  occur  in 
all  veins.  According  to  this  view  these  famous  mines  should  Lave  before  them  a 
renewal  of  their  former  extreme  wealth  when  this  poor  zone  has  been  worked 
through. 

More  than  900  veins  are  known,  which  have  been  classed,  according  to  the  ores 
they  yield,  in  four  groups  : 

1.  The  quartz  group,  containing  about  150  veins,  from  3  inches  to  6  or  7  feet  wide. 
This  would  probably  be  called  in  America  the  silver  group,  for  its  va'uaMe  min 
eral  consists  mostly  of  various  silver  minerals.  The  gangue  is  quartz  with  some 
gneiss,  and  the  ores  are  silver  glance,  ruby  silver,  fahlerz,  miargyrite,  polybasite, 
brittle  silver  ore,  antimony  glance  and  antimony  sulphide. 


FREIBERG.  OS, 

2.  Tlie  pyritiferous   group,  with  about  300  veins,  of  2  inches  to  3  feet  width. 
The  gangue  is   chiefly  quartz,  with   some   calc-spar,    iron-spar,   heavy-spar  and 
fluor-spar.    The  principal  ores  are  argentiferous  galena,  blende,  pyrites,  arsenical 
pyrites,  with  a  certain  proportion  of  the  m  nerals  named  in  connection  with  th  » 
first  group.     To  this  group  belong  also  the  veins  which  yield  chi  fly  copper  ores  ; 
as  copper  pyrites,  peacock  ore,  copper  glance,  red  oxide  and  carbonate  of  copper. 

3.  The  noble  lead  group,  so-called  fiom  its  richer  ores,  has  340  veins,  in  which 
tlte   gangue  is  brown   spar,  manganese   spar  i.nd   quartz.     The  ores   are  galena, 
richer  in  silver  than  that  of  the  preceding  division,  blende,  pyrit  s,  native  silver 
and  some  proper  silver  minerals. 

4.  The  barytic  lead  group,  with  130  veins,  some  of  them  very  wide.     The  gan 
gue  is  heavy  spat',  with  some  fluor-spar  and   quartz,  and  the  on  s  are  galena, 
blende  and  pyrites,  w  th  some  carbonates  and  silver  minerals. 

The  ores  obtained  from  these  extensive  mines  may  be  briefly  described  as  con 
taining  all  the  lead,  silver  and  copper  minerals,  that  are  not  mere  cabinet  curi 
osities,  besides  most  of  those  that  are  ^-uch.  The  total  quantity  delivered  in  1867, 
was  34,163  tons  (2,000  Ibs.)  which  contained  by  assay  : 

Per  Cent,  In  1  Ton. 

71,444-25  pounds  silver  and  gold  =    0-104  30-47  ounces. 

5,130-00  tons  lead  =  15-01  300-20  pounds. 

78-75     "      copper  =    0-23  4 -GO  pounds. 

664-25     "      zinc  '==     1-94  38-80  pounds. 

174-50     "      arsenic  =    0-51  11-20  pounds. 

There  are  two  establishments  at  Freiberg,  the  Muldner  and  Hals  riicke  Works. 
Differences  in  the  composition  of  the  ores  have  given  rise  to  slight  deviations  in 
treatment,  and  for  the  sak*  of  consistency  this  pai  er  will  deal  with  the  course  oi 
operations  at  thn  Muldner  Works  alone,  while  that  in  use  at  Halsbrucke  will  not 
be  rt- ferred  to,  except  in  describing  the  copper  treatment  which  is  carried  on  only 
there. 

The  Muldner  Works  treated  in  1867,  16,702  tons  of  ore  and  furnace  products, 
which  contained  by  assay : 

Per  Cent.      In  1  Ton. 

43,197-45      Av.pounds        silver  0-129  37-02      Troy  oz. 

106-89  "  gold  0-00032          0-093          '  « 

4o4-41  "  bismuth  0-0014  0-03         pounds. 

608-88  «  nick'l<fc  cobalt  0-00 18  0-04 

7,520,70400  "  lead  22-51  450-02        '     «' 

137,445-90  "  copper  0-41  8-20  " 

'    7,702,54663  or  3.851  tons. 

By  comparing  this  table  with  that  above  given,  it  will  be  observed  that  the  ore 
treated  at  the  Mulduer  Works  appears  to  be  richer  than  the  great  average.  This 
is  because  a  great  amount  of  furnace  products  are  added  to  the  ore,  becau-e  nearly 
all  the  foreign  ores  are  taken  to  this  establish ment,  which  lies  immediately  uu  the 
railroad,  while  the  other  works  is  sev:  ral  miles  from  it.  These  Jo  eign  ores  are 
much  richer  than  the  average  Freiberg  ore,  as  the  fact  that  they  a  e  able  to  bear 
a  transportation  of  several  thousand  miles,  and  still  afford  a  prolit,  indicates. 


56  FREIBERO. 

The  total  amount  of  these  products,  according  to  the  table,  is  3,851  tons,  or 
very  nearly  25  per  cent  Seventy-five  per  cent,  of  the  ore  is  therefore  material 
which  must  be  removed.  This  material  is  of  two  kinds,  useful,  as  sulphur  and 
arsenic  ;  und  worthless,  as  quartz  and  other  gangue.  The  useful  constituents  are 
economised  as  much  as  possible,  and  this  gives  rise  to  a  series  of  operations 
which  are  supplementary  to  the  regular  course  of  smelting. 

Thirteen  different  products  are  obtained  as  follows  : 
Metals.  Products. 

1  Gold.  1  Sulphuric  acid. 

2  Silver.  2  Copper  vitriol. 

3  Lead.  3  Arsenic,  white  and  yellow. 

4  Zinc.  4  Orpiment,  or  ar.^enic  sulphide. 

5  Arsenic.  5  Speise,  containing  cobalt  and  nickeL 

6  Bismuth.  6  Zinc  paint. 

7  Platinum. 

The  process  is,  however,  primarily  one  for  the  extraction  of  lead  and  copper, 
•with  their  accompanying  gold  and  silver,  the  rest  being  all  bye  products.  Cer 
tain  preliminary  operations  have  to  be  undertaken  in  order  to  prepare  the  ores 
containing  arsenic,  sulphur  and  zinc,  but  holding  no  lead,  for  the  fusion  with 
1-nd  ores  in  which  they  part  with  their  silver.  These  preliminary  steps  have  been 
group*  d  together  in  the  following  paper  in  a  PREPAHATORY  SERIES  of  operations. 
Then  follows  the  REGULAR  SERIES,  in  which  all  the  operat  OLS  connected  with  the 
fusion  of  the  lead  or-  s  and  the  extracti  n  of  the  silver,  gold  and  copper,  are 
placed.  Finally,  in  a  SUPPLEMENTARY  SERIES,  are  given  the  operations  in  which 
marketable  articles  are  prepared,  not  from  ores,  but  from  various  products  ob 
tained  during  the  coui  se  of  the  previous  work. 

Only  by  keeping  in  mind  the  fact,  that  there  is  one  leading  series  of  operations, 
which  has  for  its  object  the  production  of  lead,  silver,  gold  and  copper,  and  upon 
which  a  1  the  other  work  is  dependent,  can  a  clear  idea  of  the  varied  methods  in 
use  at  Freiberg,  be  obtained. 

The  processes  placed  in  these  three  series  are  as  follows  : 

Preparatory.  Regular.  Supplementary. 

Manufacture  of  Arsenic.  Fusions  for  Lead.  Bismuth  Process. 

"         "    Sulphuric  Acid.  Treatment  of  Matte.  Hard  Lead  Process. 

'<         "    Zinc.  Cupellation.  Separation  of  Gold. 

11         "    Zinc  Paint.          Treatment  of  Copper.        Manuf.  Platinum. 
Treatment  of  Lead.  Kenning  Arsenic. 

Seven  sorts  of  ore  are  recognized  : 

1.  Pyrites;  iron  pyritts  containing  not  more  than  1  per  cent,  copper,  or  15 

per  cent,  zinc,  and  little  arsenic. 

2.  Arsenic  ores  ;  averaging  35  per  cent,  metallic  arsenic. 

3.  Arsenical  pyrites  ;  15  per  cent,  arss'.ic,  26—28  per  cent,  sulphur. 
4    Arsenical  le  id  ores  ;  12  per  cent  arsenic,  18 — 20  per  cent.  lead. 
5.  Blende  ;  with  more  than  30  per  cent  zinc. 

6»  Pyritiferous  ores  ;  containing  15—30  per  cent.  zinc. 

7.  Lead  ores  ;  1,  gale7ia,  with  more  than  30  per  cent,   leud,  and  2,  plumhifrioua 
ore,  with  15—29  per  cent.  lead. 


FREIBERG.  57 

But  foil  :wing  the  system  pursued  in  this  paper,  the  old  classification  into 
fluxes,  load  ores,  dry  ores  and  copper  ores,  will  be  retained.  The  fluxes  are  in 
the  main  those  which  contain  so  much  iron  as  to  make  them  valuable  additions 
to  the  fusion  for  lead.  They  are  chiefly  iron  pyrites  containing  arsenic  and  zinc  ; 
but  the  zinc  ores  also  belong  in  this  class,  tha  residues  after  the  distillation  of 
the  zinc  being  carried  to  the  lead  process  and  added  in  the  roasting  furnace. 
The  dry  ores  (Durrerze) ,  are  s  >  called  from  the  absence  of  lead.  In  this  country 
they  would  be  called  distinctively  silver  ores,  for  their  valuable  part  consists  of 
true  silver  minerals.  They  are  worked  with  the  le  id  ores  in  the  shaft  furnace, 
and  therefore  come  in  the  regular  series.  But  if  their  quantity  is  too  great  to  be 
disposed  of  in  this  way,  they  can  be  melted  in  a  reverberatory  with  slag  from  the 
fusion  for  lead,  and  than  belong  to  the  preparatory  series.  This  was  formerly 
the  basis  of  the  Freiberg  treatment.  Now  it  is,  at  most,  an  exceptional  opera 
tion. 

PREPARATORY  SEKIES  OF  OPERATIONS. 

Roasting  .-—Chief  among  these  operations  is  roasting,  or  the  removicg  of  the 
sulphur.  For  this,  four  varieties  of  furnace  are  used  :  1.  kilns  ;  2.  Gorstenhofer 
furnaces  ;  3.  Wellner's  stalls  ;  4.  reverberatory  furnaces.  The  first  two  are  con 
nected  with  the  sulphuric  acid  chambers.  Kilns  are  used  for  ore  in  lumps,  and 
for  matte.  Those  in  which  ore  is  roasted  are  10  feet  high,  and  7X5  feet  in  sec 
tion  ;  those  for  matte  are  10  feet  high,  and  10X5  feet  in  section,  the  long  side  in 
both  cases  lorming  the  front.  They  have  numerous  sni;ill  side  openings  through 
which  the  workmen  can  observe  and  regulate  the  operation.  The  charge  for  the 
larger  furnaces  is  1,760  to  2,200  pounds,  and  for  the  smaller  650  to  1,300  pounds. 
A  charge  is  drawn  every  twelve  hours,  so  that  one  kiln  roasts  in  twenty-four 
hours,  of  matte  3,500—4,400  pounds,  and  of  ore  1,300—2  600  pounds.  No  fuel 
is  used.  The  sulphur  is  reduced  to  8  per  cent.  When  it  is  necessary  to  roast 
the  coarse  ore  or  matte  more  thoroughly,  Wellner's  stalls  are  employed.  These 
have  grates  upon  which  a  fire  is  maintained,  by  which  the  sulphur  is  more  tho 
roughly  removed  than  can  be  done  by  any  heat  produced  by  its  own  combustion. 
But  as  sulphur  is  needed  in  the  shaft  furnace,  the  re-roasting  of  these  coarse 
ores  is  rather  exceptional. 

For  fine  ores,  the  Gerstenhofer  furnace  is  employed  for  preliminary  roasting. 
The  form  of  this,  as  is  well  known,  is  that  of  an  upright  shaft  containing  trian 
gular  bricks,  reaching  from  side  to  side,  the  upper  surfaces  of  which  form  shelves 
on  which  the  ore  periodically  rests.  These  furnaces  have  not  answered  the  ex 
pectations  formed  of  them,  and  they  are  retained  at  Freiberg  more  as  the  best 
construction  in  some  respects  that  has  yet  been  devised  for  finely  crushed  ores, 
than  as  a  thorough  roasting  apparatus.  They  do  not  reduce  the  sulphur  beyond 
12  or  13  per  cent.,  and  are  used  as  a  preparation  for  reverberatories.  The  roast- 
iirg  is  not  always  uniform  ;  but  for  fine  ore,  they  are  almost  the  only  resort  of  the 
sm.-lter,  who  wishes  to  utilize  his  sulphur  in  the  manufacture  of  sulphuric  acid. 

Boasting  only  to  13  per  cent.,  these  furnaces  require  to  be  supplemented  by 
reverberatories  an  int-  resting  variety  ot  which  is  found  at  Freiberg.  They  are 
all  long  furnaces,  the  ore  gradually  advancing  from  the  cool  to  the  hot  end. 
Three  kinds  are  in  use,  double  hearth  furnaces  of  47  and  of  76  leet  hearth  length^ 


58  FREIBERG. 

and  single  hearth  furnaces  ;  both  sizes  of  the  former  have  upper  hearths  of  the 
width  of  6  feet  and  low«-r  hearths  of  5  feet  6  inches.  It  was  found  that  the  shorter 
furnaces  did  their  work  just  as  well  as  th^  longer,  in  less  time  and  with  less  la- 
Lor.  In  building  a  new  furnace,  it  was  therefore  made  of  47  fe^  t  heartU 
length,  the  upper  hearth  7  feet  wide  and  the  lower  6  feet  6  inches.  These  double 
hearth  furnaces,  and  especially  the  old  forms,  which  have  a  Hue  on'  top,  are  ex 
tremely  hard  to  keep  in  repair  ;  and  trial  was  made  at  the  Ha  sbriicke  works,  of  a 
single  hearth  furnace,  48  feet  long  and  10  feet  wide.  This  gives  more  hearth 
room  than  the  longest  of  the- old  furnaces,  and  allows  doors  to  be  made  on  both 
sides  ;  while  the  two-banked  furnaces  mostly  have  doors  on  one  side  only,  a  dis 
position  which  makes  it  very  difficult  -to  move  ore  that  lodges  between  the  doors. 
This  furnace  roasts  fully  as  well  as  the  older  forms,  and  also  disposes  of  about  50 
per  cent,  more  material. 

The  Gerstenhdfer  furnaces  and  the  kilns  are  connected  with  a  system  of  flues, 
in  which  the  arsenic,  which  forms  a  constituent  of  almost  all  the  pyrites,  is  con 
densed.  From  the  flues  the  sulphurous  acid  vapors  pass  to  the  lead  chambers, 
where  sulphuric  acid  is  made.  This  condensation  system  is  peculiar  in  having 
canals  next  the  acid  chambers,  formed  of  sheet  lead,  by  whuh  the  gas  is 
BO  much  cooled  as  to  insure  tho  most  thorough  precipitation  of  the  arsenic.  The 
gi?s  also  reaches  the  chambers  in  the  best  condition  for  condensation.  The  re- 
verbt ratory  furnaces  have  a  special  system  of  canals,  in  which  a  dust,  very  rich 
in  arsenic,  collects.  As  the  gas  is  not  utilizable  lor  sulphuric  acid,  the  canals 
end  in  a  high  chimney.  With  this  description  of  the  means  for  roasting,  we  will 
pass  to  the  treatment  of  the  various  sorts  of  ore  which  are  subjected  to  it. 

Pyrites  : — The  coarse  ore  is  roasted  in  kilns  to  about  8  per  cent ,  and  if  desired, 
it  is  re-roasted  in  stalls.     The  fine  ore  first  passes  through  the  Gersteuhofer  fur-4 
nace,  in  which  the  sulphur  is  reduced  to  13  per  cent.,  and  is  then  mixed  with  the 
lead  ores  for  roasting  in  a  reverberatory. 

Arsenic  ores  are  of  three  kinds.  1.  True  arsenic  ores  ;  2.  Arsenical  pyrites  ; 
and  3.  Arsenical  lead  ores.  The  true  arsenic  ores  are  treated  both  for  metallic 
arsenic,  of  which  they  contain  about  35  per  cent.,  and  for  arsenic  sulphide. 
The  operation  consists  in  a  disiillation  in  chainotte  tubes,  first  at  a  low  tempera 
ture  which  drives  over  the  arsenic  sulphide,  and  then  at  a  high  h>  at,  when  the 
metallic  arsenic  passes  over.  The  first  collects  in  the  extreme  end  of  the  con 
densing  apparatus,  and  the  second  in  that  part  nearest  the  furnace. 

Arsenic  sulphide  is  also  obtained  from  the  arsenical  pyrites  and  from  sulphu 
ric  acid  residues.  The  former  contain  about  15  per  Ct  nt.  arsenic  and  26 — 28  per 
cent,  sulphur.  This  distillation  is  also  performed  in  tubes.  The  residues  still 
containing  arsenic,  are  treated  like  the  lead  ores  described  in  the  next  paragraph. 

Arsenical  lead  ores  are  roasted  in  a  reverberatory  furnace  which  has  a  hearth 
14  feet  long  and  10  feet  wide.  In  order  to  prevent  the  passage  of  sparks  and  soot 
into  the  flues  where  the  arsenic  condenses,  the  ordinary  fir  place  is  replaced  by  a 
simple  gas  generator.  This  is  formed  by  merely  sinking  the  grate  about  3i  feet 
below  the  firebridge,  and  in  the  shaft  thus  produced  coke  is  burned.  Combus 
tion  takes  place  only  in  the  lower  part  of  the  coke  column,  and  th*  upper  part  is 
not  heated  sufficiently  to  decrepitate.  The  cha-ge  is  about  2,000  pounds,  which 
is  roasted  in  six  hours,  at  an  expense  of  275  -  330  pounds  coke  ;  each  furnace 


FREIBERG.  59 

has  a  speci  *1  flue  800  feet  long,  in  which  a  perfectly  white  dust,   free  from  soot, 
and  suitable  for  the  market,  collects. 

Zinc  ores  consist  of  blende,  which  is  roasted  with  great  care  in  reverberatories, 
by  which  the  amount  of  sulphur  is  reduced  to  one  and  a  half  per  cent.  The 
roasted  ore  is  then  distilled  in  Silesian  muffles,  and  the  residues  from  the  distil 
lation  are  mixed  with  the  roasted  pyritiferous  ores,  and  treated  as  described  iu 
the  next  paragraph.  These  residues  contain  9  —12  per  cent,  zinc  ;  1 — 2  per  cent, 
copper  ;  and  0-03 — 0.04  per  cent.  (8*7— 11*6  ounces)  silver. 

Pyritiferous  ores  are  pyrites  containing  blende.  They  have  from  15 — 29  per 
cent,  of  zinc;  1— 2per  cent,  copper;  0-015— 0-045  per  cent,  silver;  andmore  than  20 
per  cent,  of  sulphur.  Their  treatment  is  one  of  the  most  peculiar  in  the  whole  range 
of  metallurgy.  It  is  impossible  to  utilize  the  zinc  they  contain  as  metal,  nnd  yet 
it  must  be  eliminated,  if  the  ore  is  to  be  charged  in  the  fusion  for  lead,  wh-re  a 
high  percentage  of  xinc  would  seriously  disturb  the  operation.  The  ore  is,  there 
fore,  powdered  fine,  and  roasted  first  in  a  Gerstenhofer  furnace.  Residues  from 
the  zinc  distillation  are  then  added,  and  the  whole  is  roasted  in  a  reverberatory. 
The  roasted  ore  is  then  mixed  with  coke  slack  and  brown  coal,  and  smelted  at  a 
high  heat  in  a  reverberatory  furnace.  The  zinc  oxide  which  has  been  formed 
in  roasting,  is  now  reduced  to  metal  and  volatilized,  but  immediately  oxidizes 
again  in  the  air,  and  collects  in  the  flues  in  the  form  of  a  gray  dust.  This  ope 
ration  is  conducted  at  a  nearly  white  heat.  About  two-thirds  the  zinc  is  removed 
in  this  way,  and  the  product  —called  dezincing  residue — contains  all  the  iron  and 
not  quite  one-third  the  zinc  of  ths  original  charge.  The  regular  charge  con- 
sis  t-s  of 

30  roasted  ore  ;          |          1-3  brown  coal ;          |          1 -6  coke  slack. 
From  four  to  six  charges  are  fused  in  twenty-four  hours  ;  and  the  expense  of 
fuel,  according  to  the  average  of  five  days  run  in  Septemb.r,  1809,  was  :  For  re 
duction  11-5  ;  on  the  grate  30-8  ;  total  42-3  per  cent. 
Products  : 

Residues— 0-012  per  cent  (3£  oz.)  silver,  8--10  per  cent,  zinc. 
Speise,  usually  amounting  to  4  per  cent,  of  the  ore.     It  contains  018  per  cent. 

(5.2  oz. )  silver,  2  per  cent,  lead,  and  10  per  cent,  copper. 
Lead  is  sometimes  produced.     It  is  very  impure,  forms  about  0.16  per  cent,  of 

the  ore,  and  contains  1-3  per  cent.  (389  oz.)  silver. 

Flue  dust,  which  forms  about  10  per  cent,  of  the  ore,  and  contains  0-005  per 
cent.  (1|  oz.)  silver,  10  per  cent,  lead,  24  per  cent,  zinc,  and  30  per  cent, 
sulphuric  acid.  The  dust  near  the  furnace  contains  a  great  deal  of  sulphu 
ric  acid.  It  is  lixiviated  and  the  residues  returned  to  the  furnace.  The  re 
mainder  is  sold  as  paint. 

The  furnace  in  which  this  and  similar  operations  are  performed  is  an  adapta 
tion  of  that  used  in  the  English  copper  process.  It  is  a  reverberatory,  in  which 
the  lining  is  composed  of  a  mixture  of  sand,  clay,  and  slag,  sand  alone,  or  any 
other  material  that  may  be  desirable.  A  foundation  of  suitable  size  is  dug  out 
and  lined  with  masonry.  Small  pillars  of  masonry  (c  c,  Figures  7,  8,  and  9)  ara 
also  carried  ;ip  nearly  to  the  hearth  level.  On  these  strips  of  iron  plate  are  laid, 
on  which  rests  a  number  of  iron  plates,  6  6  forming  the  hearth  bottom.  Upon 


60 


FREIBERG. 


these  is  placed  a  layer  of  broken  stone  m,  then  comes  a  layer  of  quartz  and  cha- 
motte  (old  bricks  ground  up)  n,  and  on  this  the  hearth  sole,  fc,  made  up  usually 
of  quartz  and  slag,  is  melted.  The  other  parts  of  the  furnace  are  :  d,  ouier  walls 

Figure  9. 
G 


Figure  7.— Reverberator?/  Furnace  at  Freiberg. 

of  hard  burned  brick  ;  e,  fire-place  ;  /",  grate  ;  g  fire  door ;  h,  fire  bridge  of  re 
fractory  brick  ;  j,  opening  in  fire  bridge  to  cool  it ;  /,  arch  made  of  refractory 
brick  ;  o,  openings  for  admission  of  air  ;  p.  working  door  ;  q  and  r,  side  doors  ;  s, 
tap  hole  ;  t,  charging  hole  in  roof ;  u  and  v,  supports  for  the  tools  ;  w,  the  fine  ; 
and  x,  the  chimney,  made  of  hard  burned  red  brick,  cemented  with  a  mixture  oi 
quartz  and  clay.  The  whole  is  strongly  bound  with  wrought-iron  bars.  Fig.  7 
is  a  vertical  side  section,  Fig.  8  a  horizontal  section  und  Fig.  9  an  end  section  ol 
the  furnace. 

Th's  operation  is  not  one  to  be  imitated  except  under  peculiar  circumstance?, 
for  it  is  so  costly  and  its  product  of  so  little  value,  that  the  proceeds  hardly  more 
than  cover  expenses.  At  Freiberg,  it  is  valuable  for  other  reasons  than  pecuni 


FEEIBERG. 


61 


ary  profit.  One  of  the  greatest  defects  of  the  Freiberg  ore  was  formerly  its  lack 
of  iron,  a  want  which  was  one  of  the  reasons  that  in  former  times  led  to  the  adop 
tion  of  a  reverberatory  furnace  process,  after  a  trial  of  the  shaft  furnace  had  failed. 
Freiberg  produces  iron  pyrites  mixed  with  zinc,  but  this  source  of  iron  was  use 
less  until  this  method  of  eliminating  most  of  the  zinc,  was  discovered.  To 
merely  roast  the  ore  and  add  it  to  the  charge  in  the  shaft  furnace  would 
cause  the  entrance  of  so  much  zinc  into  the  slag  that  it  would  be  both  pasty 


and  nearly  infusible.  But  by  distilling  the  zinc  off,  a  residue  rich  in  iron 
and  comparatively  poor  in  zinc,  is  obtained  ;  and  this  forms  a  very  accep 
table  addition  to  the  lead  ores. 

REGULAR  SERIES  OF  OPERATIONS. 

From  all  the  above  operations  we  have  the  following  products  : 
1.  From  Sulphur  ores— Roasted  iron  pyrites  containing  some  lead,   copper  and 
silver. 


62  FREIBEKG. 

2.  From  Arsenic  ores — Roasted  residues,  having  in  the  main  the  composition  of 

roasted  iron  pyrites  and  still  containing  a  certain  pro 
portion  of  arsenic,  together  with  lead,  copper  and 
silver. 

3.  From  Zinc  ores — Dezincing  residues,  forming  a  Blag,   which  contains  much 

iron,  8—10  per  cent,  zinc,  with  lead,  copper  and  sil 
ver  ;  also  a  speise  containing  very  much  arsenic  with 
iron,  copper,  lead,  cobalt  and  nickel. 

Besides  these,  the  following  ores  remain  for  treatment :  1.  Galena  ores.  2. 
Lead  bearing  ores  ;  (the  average  of  the  two  is  barely  40  per  cent,  lead  and  0.15 
percent.,  (43 1  oz.)  silver.)  3.  Copper  ores.  4  Dry  ores. 

The  treatment  now  becomes  that  known  as  the  Roasting  and  Reduction  pro 
cess  ;  the  ores  being  first  roasted  to  a  silicate  and  then  reduced  in  the  shaft  fur 
nace.  In  the  former  operation  various  purchased  materials  containing  gold  aud 
silver,  together  with  the  residues  from  arsenic  glass  are  added,  and  the  products 
mentioned  above  serve  as  flux  in  the  blast  furnace.  It  is  for  this  reason  that  the 
ores  from  which  they  have  been  obtained  have  received  the  name  Fluxes.  The 
first  step  is  to  make  the  "  ore-mixture"  for  roasting.  This  is  done  by  spreading 
out  in  thin  layers,  one  upon  the  other,  the  different  lots  of  ore,  so  that  by  cut 
ting  the  mass  down  vertically,  the  charges  taken  daily  for  the  furnace  will  have  a 
pretty  uniform  composition.  This  is  of  great  importance  in  its  effect  both  upon 
the  roasting  and  also  upon  the  regular  working  of  the  shaft  furnace.  The  mix 
ture  contained  in  1867  : 

60-64:5 lead  ores. 

18  -Hi "  dry"  or  silver  ores. 

1  -703 copper  ores. 

11  -779 purchased  products  and  flux. 

7*759 foreign  ores. 

100- 

It  contained  on  the  average  0-2425  per  cent,  silver  (70|  oz.),  29-08  per  cent 
lead,  and  0.156  per  cent,  copper. 

Boasting  : — The  mixed  ore,  which  is  in  the  state  of  powder,  is  roasted  in  the 
reverberatory  furnaces  before  mentioned.  Experiment  has  proved  that  a  hearth 
of  47  feet  length,  and  a  grate  of  25  inches  width,  is  sufficient  to  insure  a  thorough 
use  of  fuel  with  the  above  mixture  of  ores.  The  charge  is  made  in  posts  of  1,650 
pounds  each,  which  are  introduced  every  three  hours,  so  that  a  furnace  roasts 
13,200  pounds  in  twenty-four  hours.  The  thickness  of  the  layer  of  ore  is  six  in 
ches.  It  should  be  remarked,  however,  that  the  new  single  he  >rth  furnace,  at 
the  Halsbriicke  works  roasts  21,120  pounds  daily.  A  great  difference  in  the 
amount  of  labor  is  also  apparent.  The  76-foot,  double  hearth  furnaces  require 
eight  workmen  to  twelve  hours  ;  the  47-foot  furnaces,  five  men.  Fuel  amounts  to 
22£  per  cent,  o:  the  ore,  but  the  coal  is  of  very  poor  quality  and  will  avernge  20 

25  per  cent,  of  ash.  Well  roasted  ore  contains  3—5  per  cent,  sulphur,  and 

rarely  reaches  6  per  cent.  The  ore  is  thoroughly  iused  and  comes  from  the  lur- 
uace  as  a  silicate. 

Reduction  takes  place  in  the  octagonal  or  "Piltz"  furnace,  as  it  is  named  after 


FREIBERG.  63 

its  inventor.  This  was  as  nrst  made  octagonal,  but  new  ones  are  to  be  round. 
The  earlier  forms  were  wider  at  the  top  than  at  the  bottom,  but  the  new  ones  are 
to  have  straight  sides.  The  new  furnaces  then  will  differ  from  the  old  7-tuyere 
Stolberg  furnaces  only  in  having  one  tuyere  more,  in  having  tuyeres  on  all  sides, 
(and  theref  ire,  being  cooled  on  all  sides, )  and  in  being  closed  at  the  top  ;  their 
lower  walls  are  only  one  bride  thick,  but  this  is  a  matter  of  convenience  only  and 
cannot  have  any  material  effect  upon  the  working.  Thinness  of  walls,  in  fact, 
has  no  other  effect  than  to  cool  the  hearth  and  thus  prevent  its  rapid  destruction. 

The  furnace  is  built  in  two  parts.  The  iipper  part  is  built  of  any  hard  brick, 
is  surrounded  by  a  shell  of  strong  sheet  iron,  and  is  carried  upon  eight  iron  col 
umns.  It  stands  4£  feet  above  the  sole  of  the  hearth.  Its  shape  being  conical, 
and  the  base  of  the  cone  forming  the  top,  the  lining  rests  upon  the  iron  shell, 
but  the  lower  courses  are  also  kept  in  place  by  a  ring  which  is  fastened  to  tha 
shell  by  means  of  an  angle  iron. 

The  mode  of  supporting  the  shell  upon  the  iron  columns  is  somewhat  peculiar. 
On  four  of  the  eight  sides,  a  strip  of  angle  iron  is  bolted  to  the  shell.  Tnese  rest 
upon  an  I  beam  bent  to  a  square  with  rounded  corners  ;  and  this  I  beam  rests  on 
the  columns.  The  columns  are  not  placed  equi-distautly  around  the  furnace,  but 
are  assembled  in  pairs  on  those  sides  where  the  angle  iron  is  bolted  on.  At  the 
level  of  the  distributing  air  pipe  brackets  are  placed  on  t  ach  side  of  the  columns. 
Those  on  the  outside  carry  the  disiributiug  pipe.  Those  next  the  furnace,  bear 
against  angle  iron  knuckles  which  are  bolted  to  the  shell,  on  those  sides  which 
do  not  carry  the  angle  iron  strips  further  up. 

The  top  of  the  furnace  is  formed  by  a  round  iron  hopper  or  cone,  the  opening 
of  which  is  about  20  inches  less  than  the  diameter  of  tne  furnace.  From  this 
an  iron  cvlinder  projects  into  the  furnace,  leaving  an  open  annular  space  uf  seven 
inches  between  the  cylinder  and  the  lining.  The  top  of  this  cylinder  is  closed  by 
a  plain  cylindrical  sheet  iron  cup,  resting  on  the  inner  surface  of  the  hooper. 
The  discharge  flue  is  placed  in  the  side  immediately  opposite  the  cylinder. 

Th<}  charge  is  made  in  the  hopper,  around  the  cup,  and  is  thrown  into  the  fur 
nace  by  raising  the  cup.  It  falls  into  the  cylinder,  and  thence  passes  to  the  body 
of  the  furnace.  The  gas  produced  by  the  combustion  of  the  fuel  not  b>  ing  able 
to  leave  the  furnace  by  the  throat,  collects  in  the  annular  space  around  the  cylin 
der,  and  passes  off  by  the  flue.  The  flue  is  lined  with  firebrick,  three  inches 
thick. 

This,  as  will  be  seen,  is  an  old  form  of  charging  apparatus,  well  known  to  iron 
smelters.  Other  methods  are  also  in  use  at  Freiberg,  in  which  the  gas  passes  off 
by  a  central  pipe,  running  through  the  cup.  The  reason  for  making  the  change 
was,  that  the  syst  m  of  flues  is  not  sufficiently  large  for  the  work  it  has  to  do  and 
the  furnace  sometimes  failed  to  draw.  The  central  pipe  permi  s  a  direct  dis 
charge  into  the  atmosphere  whenever  necessary. 

The  foundation  is  carried  deep  into  the  ground,  and  is  surrounded  by  2-inch 
plates  of  c.'st-iron.  It  consists,  in  fact,  of  an  8 -sided  iron  box,  lined  with  u;a- 
sonry.  The  center  is  filled  up  with  sl*g,  rubble,  clay  and  bricks.  Upon  the 
masonry  the  hearth  walls  are  built  ;  and  tue  hearth  material,  composed  of  clay 
and  coke  slack  is  laid  on  the  bricks 

From  this  description,  it  will  be  seen,  that  the  effective  height  of  the  furnace. 


64 


FKEIBERG. 


that  is,  the  height  through  which  the  products  of  combustion  act  on  the  charge, 
is  that  from  the  sole  to  the  lower  edge  of  the  cylinder,  or  fifteen  feet  four  inches. 


Figure  1O. — Shaft  Furnace  at  Freiberg.    Vertical  Section. 


The  dimensions  of  the  furnace,  reduced  from  French  measure,  are  as  follows  : 
Height  from  sole  to  top 17  feet  10  inches. 


1 '        of  cylinder. . . : 2 

"        of  slag  discharge  over  sole 1 

'•        of  tuyeres  over  sole 1 

Diameter  at  tuyeres 5 

"        at  top 6 


FREIBERG.  65 

Diameter  of  cylinder 5  feet  3  inches. 

of  tuyeres ' 0  "  2$    •• 

Number  of  tuyeres  (water  cooled) 8 

Hopper  ;  Height 1  ft.  9    in. 

Diameter  at  top 8  «  9      " 

"        at  bottom 4  "  8      " 

Cup;  Height 2  "  4      " 


Diameter 5 

Blast  pipes  ;  Diameter  of  distributing  pipe  (interior) 1 

"         of  nozzle  pipes 0 

Discharge  flue  ;  Diameter  (interior) 1 

Reception  basin  ;  Diameter 4 

Depth 1 


Slag  pot ;  Height 2 

Diameter  at  top 1 

Columns  ;  Mean  Diameter. 64 

Height 14    "      2 

The  charge  for  the  furnace  is  marie  up  in  layers  like  the  ore-mixture,  only  not 
so  carefully.  Messrs.  K.A.sr  and  BUA.UNING  give  the  following  as  its  composition  : 

Boasted  ore 100 

Baw  matte 15 

Boasted  pyrites  from  the  kilns    15 

Slag  from  the  same  operation 80 — 100 

210—230 

But  generally  other  products  are  worked  into  the  charge  such  as  arsenic  resi 
dues,  zinc  residues,  lead  bearing  produc  s  and  purchased  material,  containing 
gold.  Two  furnaces  (Stolberg)  were  in  September,  1869,  running  on  the  follow 
ing  mixture  of  ores  and  products. 

1  II. 

Boas  ea  ore 100  100 

Slag  from  same  operati  n 150  113.6 

Baw  matte 20 

Gold  scraps 1-25 

Dezincing  residue. 10'9 


271-25       224-5 

Freiberg  ores  contain  gold,  but  in  too  small  quantity  to  pay  for  extraction 
alone.     But  by  increasing  the  proportion  through  the  addition  of  gold  scraps  the 
whole  is  obtained.     We  have  already  seen  that  the  material  treated  in  1869,  con 
tained  as  much  as  106  pounds  of  this  metal. 
Products  :—L  ad,  containing  0-5  per  cent.  (146  oz.)  silver. 

Matte,  0-2  per  cent  (58^  oz.)  silver,  25  per  cent,  lead,  and  6  per 

cent,  copper. 

Slag,  0-005  per— 0-010  per  cent.  (0.6 — 1  oz.)  silver,  5  lead. 
Flue  dust  forms  1£  per  cent,  of  the  ore.     It  contains  0.005 — 0*01  per 

cent,  silver,  and  37—40  per  cent.  lead. 

Of  coke,  containing  15 — 20  per  cent,  of  ash,  10—11  per  cent,  is  used.  The 
pressure  of  blast  is  | — 1  inch  of  mercury  or  | — £  pound  per  square  inch.  One 
smelter,  two  chargers,  and  two  to  three  slag-men  are  required  to  each  shift. 

Although  the  amount  of  silica  in  the  charge  is  less  than  is  considered  advan 
tageous  in  most  lead  works,  no  effort  is  made  to  increase  it,  but  on  the  contrary 


66 


FREIBERG. 


basic  fluxes— limestone  and  fluor  spar  are  added.  The  result  is  a  f-lag  which  is 
but  little  above  a  proto-silicate.  The  regulation  of  the  charge  depends  upon  the 
amount  of  zinc  present,  'io  avoid  the  form, ition  ot  an  infusible  zinc  slag,  the 
proportion  of  sulphur  is  kept  up,  either  by  riot  roasting  ihe  ore  c  inpletely  or  by 
at"1  ding  raw  ores  or  matte.  This  insures  the  passage  of  part  of  the  zinc  into  the 
matte  while  another  part  unites  with  the  slag.  The  amount  of  zinc  present  also 


B 


figure  11.— Horizontal  Section. 

influences  the  proportion  of  slag  repassed.  At  Halsbru'cke,  where  the  ores  con 
tain  less  zinc,  the  charge  of  slag  from  the  same  operation,  is  but  one-half  that 
used  at  the  Mulden  for  zinciferous  ores.  This  slag,  according  to  Messrs.  KAST  and 
BRAUNING,  contains  : 

Barium  Oxide 3'58 

Manganese  oxide 2-10 

Lead  oxide 1-47 

Copper  suboxide 0. 16 

Sulphur 1-85 


Silica 31-15 

lion  oxide 41-31 

Zinc  oxide 7  85 

Alumina 3-18 

Lime 6-45 

Magnesia 1-06 

100'17 

The  slag  is  received  in  conical  iron  pots.  A  certain  amount  of  tLe  lead  and 
matte  contained  in  it  settles  to  tbe  bottom  and  the  points  of  the  cones  are  broken 
off  and  sent  at  once  to  the  next  fusion.  The  amount  of  material  treated  in  the 
lead  process  in  1867  was  18, 359  tons,  made  up  as  follows : 


FRFIBEECL  67 

9,071  tons  lead  ore. 
3,330    "    dry  ore  and  copper  ore. 

5,303    "    products  containing  iron  (chiefly  from  the  Preliminary 
Series  of  Operations.) 

3>i4    "    arsenic  residues. 

270    "    iron  ore 

THE   TREATMENT   OP   THE   MATTE. 

Tho  matte  is  roasted  in  kilns  or  stamped  and  roasted  first  in  the  Gerstenhofer 
furnace,  and  when  it  is  desired  to  reduce  the  amount  of  sulphur,  in  the  reverbe- 
ratory  furnaces  also.  It  is  then  smelted  with  the  addition  of  slag  from  the  first 
fusion. 

The  operation  is  in  fact  a  treatment  of  the  first  slag  with  addition  of  the  matte, 
and  it  exhibits  in  the  strongest  manner  the  peculiarities  of  'h  Freiberg  methods. 
Though  the  matte  is  altogether  basic,  little  acid  flux  is  added  ;  and  even  the 
slight  amount  of  silica  added,  is  swallowed  up  by  the  limesto'  e  and  fluor  spar 
which  constantly  f  Tin  part  of  the  charge.  Th"  aim  is  to  produce  a  very  basic, 
thin  slag,  which  on  account  of  its  fluidity  will  allow  the  ma'te  and  lead  to  settle 
as  perfectly  as  possible. 

The  charge  varies  very  much,  for  this  fusion  is  the  general  outlet  of  whatever 
the  works  afford  of  basic  products.  Messrs.  KAST  &  BBAUNING  give  tho  follow 
ing  as  a  specimen  :  They,  it  will  be  o!  served,  base  the  charge  upon  the  amount 
of  first  slag  it  contains.  This  view  is  certainly  correct,  as  this  slag  forms  by  far 
the  largest  part  of  the  charge,  and  the  operation  is  really  a  refusion  of  slag. 

Slag  from  firstfusion  ...........  .  ........  100-0        Speise  ................     1-0 

Copper  slag  ..............  ..............     4-0        Dezincing  Residues  .  ^  .      10 

Copper  matte  raw  ......................     23        Limestone  ............     2-0 

Lead  matte  roasted  in  kilns  ..............     4.3        Fluor  spar  ............     2-0 

Lead  matte  roasted  in  kilns  and  stalls  ----     8-  4        Hearth,  eta  ...........     7*2 

Pyrites  ................................     9-0  - 

141-2 

Thus,  matte  and  ore  form  but  26  parts  to  100  slag.     On  September  16,   1869, 
the  charge  wa^  : 

First  si  >g  ...........  ...........................  100 

Eoasted  first  matte  ...........................     20 

Fluor  spar  ....................................     10 

Copper  slag  ..................................       5 


Labor  and  pressure  of  blast  are  the  same  as  before.     Of  fuel  13-14  per  cent,  is 
consulted,  equal  to  17  —  18  per  cent,  of  the  slag  ;  or  70  —  75  per  cent,  of  the  matte 
and  ore. 
Products  :-Lead=0.15-0-18  per  cent.  (44—52  oz.)  silver. 

2nd  matte—  0-10—  0  20  per  cent,    silver,  21  per  cent. 

lead,  and  15  per  cent,  copper. 
2nd  slag=0-002  per  cent.  (£  oz.)  silver,  1-5—2  per  cent. 

lead.     This  slag  is  thrown  away. 

Ther"  are  no  full  analyses  of  the  slag,  but  the  proportion  of  some  of  its  const! 
tuents  is  as  follows  : 

Silica  ............................  .  ...........  29-7 

Zinc  oxide.  .  ,  ..................................  8-5 


68  FREIBERG. 

Lead  oxide 2-5 

Silver 0  0025 

The  r  xtremely  basic  character  of  this  slag,  and  its  large  percentage  of  zinc,  make 
the  management  of  the  furnace  very  difficult.  When  the  Piltz  furnace  was  first  in-, 
troduced  at  the  Muldner  works,  its  height  was  made  22  feet  ;  but  its  reducing 
action  was  too  great  for  the  slag,  and  it  had  to  be  cut  down.  A  new  furnace 
which  is  to  bn  built  will  bo  eleven  feet  eight  inches  high,  the  diameter  of  five  feet 
cnj  incho  being  retained.  Its  sides  wi  1  be  straight  instead  of  it. dined. 

Third  and  Fourth  Fusions  :— The  second  matte  is  twice  roasted  and  resmelted 
with  first  slag,  the  object  being  to  concentrate  it  to  about  23  per  cent,  copper, 
when  it  is  looked  upon  as  a  copper  matte.  These  fusions  form  successive  steps 
in  the  operation  last  described.  The  working  of  the  fu  nace  is  not  stopped,  but 
a  second  or  third  matte  is  merely  substituted  for  the  first,  for  a  few  days  or  un 
til  the  whole  of  the  material  at  hand  has  been  smelted.  The  other  constituents 
of  the  charge  remain  the  same,  and  the  expense  of  labor  and  fuel  is  not  to  be  dis 
tinguished  from  that  given  for  the  second  fusion  An  old  table,  showing  the  gra 
dual  change  of  the  matte  from  a  lead  matte  carrying  about  57  ounces  of  silver  to 
the  ton,  to  a  copper  matte  with  one-third  less  silver  is  given  below  ;  but  it  is  very 
likely  that  the  new  method  has  chauged  these  proportions. 

SILVEP.  LEAD.  COPPEB. 

Decrea  es.  Decreases.  Increases. 

Per  c  nt      Oz.  Per  cent         Per  cent. 

in'20001bs. 

1st  matte 0.25 73      25 6 

2nd    do     0-23.... 6G  24 21... 15 

3d      do     0-17.... 48-96 13 32 

4th     do     0-15.... 43-75 13 42 

In  the  processes  just  described,  the  ores  have  all  bt.en  treated  and  resolved 
first  into  t  e  side  products  obtained  in  the  preliminary  series  of  operations  ;  and 
into  two  others  —lead  and  copper  matte — the  result  of  the  shaft  furnac  treatment. 
In  the  lead  is  concentrated  nearly  all  the  gold  and  silver,  and  the  remaining  ope 
rations  of  the  regular  series  are  those  belonging  to  the  lead  treatment,  by  which 
the  gold  and  silver  are  separated  from  the  former  metal ;  and  tliose  belonging  to 
the  copper  process,  in  which  copper,  vitriol,  and  rich  silver  residues  itre  ob 
tained. 

TREATMENT  OF   THE   LEAD. 

The  lead  obtained  in  the  foregoing  operations  contains  a  very  appreciable 
amount  of  iron,  copper,  arsenic,  and  antimony.  It  is  nil  refined  by  heating  in  a 
reverber.itory  furn  .ce,  with  admission  ot  air.  The  above  metals  are  all  more  oxi- 
dizable  than  lead,  and  a  product  is  obtained  in  which  they  are  concentrated. 
This  is  used  to  make  hard  lead,  while  th*  refiued  metal  goes  through  the  Patti- 
son  process,  for  the  extra  tion  of  its  silver.  The  latter  process  lias  been  so  often 
described,  that  it  will  not  be  followed  here.  Fourteen  kettles  are  in  use,  each  of 
27,500  pounds  capacity  ;  concentration  proceeds  on  the  one-third  system,  and 
poor  le  id  is  obtained  with  0-0015  per  cent,  silver,  and  rich  lead  of  1-5  percent.— 
1  8  per  cent.  (437—505  oz.)  silver.  The  consumption  of  fuel  in  twenty-four 
hours  is  4,220  pounds. 


FKEIBERG. 


69 


Figure  23. 


70 


FREIBERG. 


Refining :— Two  furnaces  are  in  use,  one  shallow  and  one  deep,  the  dimensions 
having  a  marked  effect  upon  the  consumption  of  fuel. 
The  shallow  furnace  treats  10  tons  in  24  hours,  with  2,200  pounds  coal. 
The  deep  "          "    13-6— 16  tons     "          "    1,320— 1760  pounds  coal 

In  spite  of  this  extreme  difference  in  fuel,  the  saving  by  the  deep  furnace  is,  at 
Freiberg,  but  a  few  cents  to  a  ton  of  lead ;  the  coal  being  very  cheap. 
Products  :• — Lead,  containing  0'6  per  cent.  (175  oz.)  silver. 

1st.  Abstrich,  which  amounts  to  about  19  per  cent,  of  the  charge. 
It  contains  a  great  deal  of  lead  arsenate  and  antimonate,  and 
a  little  copper  and  iron  sulphide. 

2nd.  Abstrich,  forming  10  per  cent,  of  the  charge,  and  containing 
but  little  arsenic  or  antimony.  This  is  returned  to  the  first  fusion 
for  lead. 

Cupellation  is  performed  in  a  German  hearth.  It  is  divided  into  three  stages, 
forming  three  separate  operations.  1.  The  operation  is  stopped  at  the  point  at 
which  the  bismuth  begins  to  oxidise.  This  takes  place  when  the  lead  is  so  con 
centrated  as  to  contain  about  50  per  cent,  silver.  2.  The  rich  lead  is  then  re 
moved  to  a  new  furnace  and  concentrated  to  about  85—  90  per  cent,  silver.  All 
the  products  contain  bismuth  and  are  treated  for  this  metal.  3.  Refining  takes 
place  at  the  Halsbriicke  works,  the  products  being  also  rich  in  bismuth. 


Figure 


Figure  IS. 


The  operation  is  performed 
in  a  cupel  furnace,  shown  in 
Figures  12, 13, 14,  and  15.  This 
is  a  round  furnace,  with  con 
cave,  or  cup-shaped  hearth,  the 
arch  of  which  is .  formed  of 
sheet  iron  lined  with  clay  and 
removable.  The  lead  is  charg 
ed  in  the  hearth  with  the  cover 
removed,  and  when  ready  the 
cover  is  placed  by  means  of  a 
crane  and  the  joint  luted  with 
clay.  There  are  five  openings 
to  the  hearth,  one  for  the 
flames  to  enter,  two  for  the 
blast,  one  by  which  the  abzug 
is  drawn  out  and  one  for  the 
discharge  of  the  litharge.  Fi 
gure  12  is  a  view  of  the  hearth 
with  the  cover  removed,  dotted 
lines  showing  the  relative  an 
gles  of  the  blast,  flame  and 
litharge  openings.  Figure  13  is 
vertical  section,  also  without 
the  cover,  and  Fig.  14  and  15 
show  the  skeleton  of  the  covtr ; 


FREIBERG.  71 

6  is  the  foundation  wall,  c  the  iron  braces,  d  drying  canals,  e  ring  wall,  often  made 
of  clay,  packed  within  an  outer  ring  of  masonry,  /  sole,  of  slag  from  lead  furnace, 
g  brick  sole  laid  on  the  slag.  This  is  laid  dry  and  the  crevices  calked  with  iner- 
gel .  Upon  this  is  stamped  a  mergel  sole  (not  shown  in  the  figure)  which  forms 
the  working  sole  of  the  furnace.  Mergel  is  an  argillaceous  limestone  stamped 
fine  and  when  of  good  quality,  contains  about  22  silica,  6  clay,  4  iron,  2  magne 
sia  and  66  lime  carbonate.  When  no  natural  rock  of  about  this  composition  is  at 
hand  artificial  mergel  may  be  made  by  mixing  intimately  1  volume  cl:iy  with  3  to 
4  volumes  powdered  limestone.  The  powder  is  sifted  through  a  mesh  of  64  holes 
to  the  sqtiare  inch.  This  is  mixed  with  old  hearth  powdered,  naoisteued  and 
stamped  in  upon  the  brick  sole,  the  layer  being  2  —  3  inches  thick.  In  stamping 
the  mass  may  be  placed  iu  layers,  the  face  of  each  layer  being  criss-crossed  before 
putting  in  the  next,  or  the  whole  may  be  put  in  at  once,  lightly  stamped  to  shape, 
and  finished  by  stamping  in  a  spiral  line  from  the  wall  to  the  center.  In  the  cen 
ter,  sometimes  nearer  the  firebridge,  a  shallow  basin  is  cut  out  where  the  silver 
finally  collects.  WheD  finished  the  sole  must  be  so  hard  that  pressure  with  the 
fingers  makes  no  impression  upon  it.  The  object  of  the  sole  is  to  absorb  the  li 
tharge  formed  in  the  last  stages  of  the  operation  It  must,  therefore,  be  porous, 
but  not  so  porous  as  to  absorb  too  much  litharge.  The  bhape  of  the  sole  has 
some  effect  upon  the  operation.  An  old  rule  is  that  with  a  deep  hearth  the  lead 
oxidizes  easier,  but  the  silver  brightens  less  easily  ;  with  a  shallow  hearth  the 
brightening  is  easier,  the  formation  of  litharge  slower. 

In  the  figures  h  and  i  are  iron  ring  braces,  k brick  w.ill  forming  the  sides  of  the 
hearth,  m  iron  plate  covered  with  mergel,  forming  the  litharge  opening  n  ;  this 
usually  has  a  hood  to  draw  off  lead  fumes  and  protect  the  workmen  ;  o  opening 
where  the  flames  escape  and  the  abzug  is  drawn  off;  this  furnace  has  no  chirn  ey 
but  is  placed  under  a  large  chimney  lorniing  the  cupelLition  room  ;  p  fire  bridge 
r  tuyeres,  u  and  v  ash  pit,  w  grate. 

The  cover  is  made  of  iron  bars  joined  by  concentric  iron  rings  upon  which  are 
placed  segments  ot  sheet  iron.  The  sheet  iron  is  pierced  with  numerous  holes 
through  which  project  bent  pieces  of  hoop  iron.  Upon  this  a  tough  clay  mixed 
with  sand  is  thrown,  forming  the  interior  surface  of  the  hood.  These  different 
parts  are  shown  in  Figure  15. 

Of  the  cupellation  a  good  idea  will  be  obtained  from  five  operations,  iu  1869, 
vhich  gave  ttie  following  results  : 

Charge  :  Lead  from  Pattinsoning 286,165  pounds. 

Produces  :  Abzug 1,100         " 

Abstrich none. 

Red  litharge 30,910 

Bismuth  litharge  4,290 

Ordinary  litharge 221,760 

Lead  scraps 3,410 

Hearth. .  .<. 25,080 

The  working  time  was  463  hours,  but  this  evidently  does  not  include  the  time 
employed  in  preparing  and  drying  the  furnace.  The  average  amount  of  lead  cu 
pelled  was  552  pounds  per  hour  ;  a  very  high  figure,  and  due  to  tbe  fact  that  to 
wards  30  tons  of  lead  are  cupelled  at  each  operation.  Of  fuel  4^  cords  wood, 


72 


FREIBERG. 


15,400  pounds  brown  coal,  and  6,610  pounds  bituminous  coal  were  used  ;  or  per 
ton  of  lead,  0-03  cords  wood,  108  pounds  brown  coal,  and  46  pounds  coal  (7 '7  per 
cent.) 

Of  the  above  products  the  red  litharge  is  sold  for  paint ;  the  litharge  containing 
bismuth  is  treated  for  that  metal;  ordinary  litharge  is  revived  to  lead,  lead  scraps 
are  returned  to  the  next  cupellation,  and  the  hearth  is  charged  in  the  first  fusion 
for  lead. 

Second  Cupellation :— The  rich  lead  is  not  weighed  but  usually  from  1,300  to 
1,800  pounds  weight,  are  obtained  at  each  operation.  From  this  second  cupella 
tion,  which  is  conducted  like  the  first,  the  following  products  are  obtained  : 

First  litharge,  containing  4  per  cent,  bismuth. 

Second  litharge  containing  9—10  per  cent,  bismuth. 

Hearth  containing  9—10  per  cent,  bismuth. 

The  time  is  four  to  six  hours,  fu»  1  9, 380  pounds  coal. 

The  resulting  silver  is  refined  in  a  cupel  furnace.  It  contains  all  the  gold  of 
the  ores  and  products,  and  this  is  separated  by  the  usual  method  of  dissolving 
the  silver  in  hot  sulphuric  acid  The  gold  remains  as  a  residue,  and  th-e  silver  is 
precipitated  by  copper  from  the  solution.  The  gold  is  ignited  with  saltpeter  and 
melted  with  bisulphite  of  soda.  The  slag  contains  platinum,  which  is  obtained 
from  it  in  the  chemical  laboratory 

THE   COPPER  PROCESS  .2 

Hitherto  we  have  followed  the  course  of  the  operations  as  they  are  carried  out 
at  the  Muldner  works  ;  n  >w  we  will  turn  our  attention  to  the  Halsbriicke  works 
where  all  the  copper  is  extracted.  The  matte  is  subjected  to  one  more  opera 
tion,  by  which  its  percentage  of  copper  is  increased  to  73  —75  per  cent.  This 
is  done  by  a  peculiar  process. 

The  first  copper  matte,  according  to  analysis  ma'le  in  the  Clausthal  laboratory 
(and  the  specimen  may  be  looked  upon  as  a  iair  average,  though  the  copper 
sometimes  rises  to  43  per  cent.),  is  made  up  as  follows  :  — 

Copper 32-9        Iron 19-5 

Sliver  0-25        Sulphur 23-8 

Lead 15. 

Arsenic,  antimony,  zinc,  nickel,  cobalt,  etc.,  in  small  quantities. 

This  is  smelted  in  a  reverberatory  furnace  with  quartz  and  barium  sulphate. 
By  reduction  the  barinm  sulphate  becomes  barium  sulphide,  which,  in  presence 
of  copper  oxide,  gives  up  its  sulphur  to  the  copper,  takes  oxygen,  and  forms  a 
silicate  with  the  quartz.  This  use  of  barium  sulphate  as  a  re-agent  is  Intended 
to  prevent  the  introduction  of  iron  into  the  charge.  Since  metallic  copper  is  not 
made,  but  copper  sulphate  inst  ad,  it  is  necessary  to  the  purity  of  the  latter  that 
the  resulting  matte  shall  not  contain  more  than  0'2  per  cent,  of  iron.  The  matte 
is  stamped  and  roasted  in  a  reverberatory  furnace,  to  5  per  cent,  sulphur.  This  is 
over-roasting,  for  there  is  not  enough  sulphur  left  to  make  the  1  asic  copper  sul 
phide  which  is  desired.  But  over-roasting  is  necessary  in  order  to  oxidize  the 

2  This  account  of  the  treatment  of  the  copper  products  is  taken  from  thn^  by  Pro- 
fe-sor  KnMemann  of  the  Claustiaal  School  of  Alines,  in  the  Preusa.  Zeitschrft  fur  b  r^;, 
Jdutten  und  tialmen  Weaen,  1872. 


FT.EIBERG.  73 

iron  sufficiently  to  insure  its  removal.  Sulphur  is  then  added  to  the  charge  in 
the  form,  as  above  stated,  of  barium  sulphate,  and  by  this  method  copper  matte, 
of  a  high  degree  of  concentration,  and  of  a  purity  that  is  hardly  attempted  else 
where  than  at  Freiberg,  is  obtained. 

Ill  roasting,  the  charge  is  1,100—1,540  pounds  of  matte  every  three  hours  ;  or 
S.bOO — 11,320  pounds  in  twenty-four  hours.  The  furnace  is  kept  cooler  than 
with  or-js  or  other  matte,  because  the  copper  matte  is  very  liable  to  soften  and 
sinter.  Of  coal  30 — 36  pel  cent  is  used,  but  it  is  of  very  poor  quality,  contain 
ing  20—25  per  cent  of  ash. 

The  produ  t  contains  copper  oxide,  basic  copper  sulphate,  iron  oxide,  basic 
iron  si  Iphate,  metallic  silver,  silver  oxide,  lead  sulphate,  zinc  oxide,  nickel 
oxide,  cobalt  <  xide,  and  arsenic  and  antimony  salts. 

This  is  fused  in  a  reverberatory  of  the  kind  des-.-ribed  when  speaking  of  the 
preparatory  operations.  The  sMes,  formed  of  clay  and  quartz  sand,  are  repaired 
after  eveiy  two  or  three  operations,  because  the  slag,  being  a  siugulo  sili  -ate. 
attacks  them  rapid'y.  The  charge  weighs  3,630 — 3,960  pounds.  Immediately 
after  charging  t^e  turnace  is  fired  as  hotly  as  possible  for  4=  -5  hours,  when  tin 
charge  is  stirred,  and  when  the  matte  has  settled,  the  scoria  is  rake  1  off.  the 
matte  remaining  behind.  A  second  charge  is  immediately  made,  and  when  the 
scoria  from  that  has  been  drawn  off,  a  taird.  Not  until  the  matte  of  three 
charges  has  collected  is  it  tapped.  Five  charges  are  made  in  twenty-four  hours. 
Ihe  following  is  the  composition  of  a  charge  : — 

Charge  :  -Roasted matte 100 

11  w  copper  (;rom  same  opera  ion)..   14—27 
Black  coppe;  (from  same  operation)    . .  23 

Barium  sulphate 25-30 

Raw  quartzose  dry  ores. .    . , 14-23 

Sometimes  fluor  spar  is  added  to  make  the  sla^  more  fusible. 
Products  :— Bla  k  copper,  containing  lead,  0-50-0-60  per  cent  silver,  20-25 

leail,  50 — 60  per  cent,  copi  er. 

Concentrated  matte  :  0-29—0-40  per  cent  i-ilver,  3— 7  p  r  cent,  lead, 
70—73  per  cent,  copper.     This  product  Ls  the  one  for  which  the 
operation  is  undertaken 
Copper  matte  :  0-30—0-40  per  cent,  silver,  9  percent,  lead,  60  per 

cent,  copper. 

Of  these  products  the  black  copper  and  copper  matte  are  returned  raw  to  the 
same  operation. 

There  was  an  apparent  loss  of  0-26  per  cent,  silver,  and  0-05  per  cent,  copper, 
and  an  apparent  gain  of  21-85  per  cent  lead,  and  296-35  per  cent.  gold.  This 
arises  from  the  fact  that  both  the  dry  ores  and  scoria  contained  lead  and  silver 
which  was  in  too  small  quantity  to  be  accounted  for  by  the  assayer,  as  in  keep 
ing  the  books  of  the  establishment  each  process  is  charged  and  credi  ed  with  the 
materials  it  receives  and  delivers  on  the  same  principles  which  gover  <  the  pur 
chase  of  ores.  The  figures  of  loss  and  profit  are,  therefore,  rot  re  ],  but 
financial. 


74:  FREIBERG. 

The  resulting  concentrated  matte  contained,  by  analysis  : 

Copper 76-4:        Iron 0-14 

Lead  4-2        Sulphur 14-05—95-08 

Silver : 0-29 

In  this  specimen  the  percentage  of  copper  is  somewhat  above  the  average.  An 
average  matte  contains  69—74  per  cent,  copper,  0-2  per  cent,  nickel  and  cobalt, 
and  0.5—1  per  cent  arsenic  and  antimony. 

This  matte  is  now  treated  with  hot  sulphuric  acid  to  extract  the  copper.  It  is 
first  stamped  dry  and  sifted  through  a  mesh  of  about  32  to  the  square  inch  in 
order  to  separate  the  metallic  copper  always  existing  in  a  matte  of  so  high  a 
grade.  This  metallic  co  per,  if  allowed  to  remain,  would  pass  through  the  dis 
solving  process  almost  undissolved,  since  the  time  of  that  operation  is  calculated 
for  the  solution  of  copper  oxide,  which  is  much  quicker  than  that  of  the  inetaL 
The  powdered  matte  is  then  roasted  d>  ad  in  an  Augustin  muffle  furnace  that  has 
three  hearths,  and  is  so  arranged  that  the  hot  gases  can  be  shut  off  wholly  or  partly 
from  the  middle  hearth,  the  object  being  to  protect  the  fresh  charge  from  the 
action  of  the  hot  gases.  If  too  hot,  the  matte  might  soften  sufficiently  to  sinter. 
One  charge  only  of  1,000  pounds  is  at  one  time  in  the  furnace,  which  for  six 
hours  is  kept  quite  dark,  the  heat  being  then  increased  for  three  hours  to  inci 
pient  whiteuess,  which  is  kept  up  for  three  hours  more  under  constant  stirring 
of  the  matte.  The  charge  remains  sixteen  hours  in  the  furnaces,  nnd  its  sul 
phur  is  reduced  to  1  per  cent.  The  roasted  ore  should  be  bluish  black  i'tom 
copper  oxide  and  not  reddish  brown  which  would  indicate  iron  oxide.  Labor 
amounts  to  about  six  days  to  2,000  |  ounds,  and  of  coal,  which  must  be  of  the 
best  quality,  110 — 120  per  ceut.  is  consumed. 

The  r  asted  matte  is  sifted  to  remove  the  lumps  formed  in  roasting.  Thee 
enclose  raw  particles  which  would  pass  unchanged  through  the  dissolving  pro 
cess  and  add  to  the  amount  of  the  argentiferous  residues.  These  course  particles 
are  stamped  arid  re-roasted  ;  the  fine  part  is  ground  in  mills  and  bolted.  It 
consist;?  of  oxides  of  copper,  iron,  nickel,  cobalt  and  lead,  metallic  copper,  silver 
and  gold  ;  a  small  quantity  of  sulphates  of  copper  and  lead  ;  and  some  arsenic 
and  antimony  salts. 

When  this  is  boiled  with  sulphuric  acid  the  oxides  are  dissolved,  but  metallic 
copper,  silver  and  gold  mostly  remain  as  a  residue.  If  silver  is  dissolved  it  is  re- 
precipitated  by  the  copper  present.  Arsenic  and  antimony  salts  are  broken  up, 
the  arsenic  remaining  in  the  liquor  as  free  arsenious  acid,  and  the  antimony  as 
antimomc  hydrate  which  partly  falls. 

The  solution  of  the  oxides  takes  place  in  thick  vats  of  hard  lead,  having  a 
capacity  of  1.25  cubic  meters,  or  about  45  cubie  feet.  They  are  1.1  meter  high 
and  1.22 — 1*30  meters  in  diameter  Kaw  chamber  acid  of  49—50°  B.  is  first  intro 
duced  to  the  height  of  0. 36  meters,  and  super  heated  steam  is  blown  in  until  the 
liquor  boils.  This  dilutes  it  somewhat.  The  povvdered  matte  is  gr  .dually  added 
by  means  of  percussion  troughs,  during  which  the  whole  is  stirred  constantly. 
One  of  the  drawbacks  of  the  Freiberg  method  is  the  tendency  of  the  matte  to 
lump  together,  thus  increasing  the  amount  of  residue.  Boiling  is  continued 
for  an  hour  and  a  half,  when  the  vat  is  filled  up  with  mother  liquor  irora  the 


FREIBERG.  75 

crystallization  tanks,  and  the  boiling  continued.  The  solution  then  marks  32°  B. 
It  is  allowed  to  settle  for  two  hours,  and  the  clear  liquor  is  then  drawn  off  by  a 
syphon  to  the  clarifying  vats,  and  afterwards  to  the  crystallization  tanks.  The 
entire  operation  lasts  fivo  hours,  and  with  four  dissolving  vats  3,630  pounds  of 
matte  are  treated  in  twenty-four  hours. 

Crystallization  continues  for  nine  days.  The  first  vitriol  formed  —about  one 
quarter  of  the  wholo — go<  s  to  the  market  as  raw  vitriol.  The  remaining  three 
quarters  is  re-dissolved,  filtered  through  granulated  copper  to  remove  the  in 
soluble  residue,  aud  also  precipitate  any  silver  tuat  may  be  in  solution,  and 
recrystallized.  This  operation  also  takes  nine  days.  The  new  liquor  is  nearly 
neutral,  and  the  crystals  are  very  large  ;  they  are  washed  to  remove  a  brown 
coatiug,  and  dried. 

The  yearly  production  is  about  2,300,000  pounds,  from  880,000  pounds  of 
matte.  The  number  of  vats  is  eight,  and  of  crystallization  tanks  104. 

The  mother  liquor  is  concentrated  by  boiling,  and  a  new  crop  of  crystals  taken. 
These  contain  0.035  per  cent  of  iron.  The  mother  liquor  is  now  very  rich  in 
iron,  but  it  also  contains  two  pounds  of  copper  to  the  cubic  foot.  It  is  used  as 
a  cementing  liquor  in  making  tine  pyritiferous  ore  into  bricks.  By  this  mea.ns 
the  copper  is  returned  to  the  process. 

The  Residues  contain  the  silver.  Th  y  are  washed,  filtered  and  dried,  and 
form  about  17  per  cent,  of  the  concentrated  matte.  Their  composition  in  1869 
was  about  1.94  per  cent,  silver,  41  ptr  cent,  lead  and  11  per  cent,  copper  ;  but 
the  proportion  of  copper  has  since  then  been  reduced  to  5  per  cent,  by  using 
stronger  acid.  The  percentage  of  lead  is  large,  because  the  sulphate  of  this  metiil 
is  entirely  insoluble,  and  lead  su'phate  is  formed  by  the  action  of  the  sulphuiie 
acid.  These  residues  are  added  to  the  first  fusion  for  lead. 

The  balance  sheet,  reckoned  upon  100  parts  by  weight  of  concentrated  matte,  is 
as  follows  : 

Charge  :— Concentrated  matte  100 

Sheet  copper  22—122 

Raw  chamber  acid  reduc-d  to  66W  B  (by  weight) 196-7— 196-7 

Products  :— Copper  sulphate 251  38 

Residues 16-41 

Mother  liquor— 3  pounds   copper  per  cubic  foot  . . .       G8  cubic  fo^t 
Do.         do.  ferruginous,  for  bricks,    21bs  copper  per 

cubic  foot 180      «• 

Labor  :— Roasting,  days  of  twenty-four  hours,   16 

Extraction,  "  7  "55 — 23-55 

Fuel  :— Roasting 116-6 

Heating  boiler 124-5 

"     liquor 100-8 

Drying  crystals 20-0 

"  residues 6-3 — 368-2 

If  to  the  above  251-38cwt  of  copper  sulphate  from  100  cwt.  of  concentrated 
matte  we  add  the  8  cwt.,  to  be  extracted  from  the  68  cubic  feet  of  3-pound 
mother  liquor,  we  have  a  total  of  259-38  cwt.  of  copper  sulphate  from  71  5  cwt. 


76  FREIBERG. 

of  copper  in  tne  matte.  Tlie  make  is,  therefore,  362 '8  per  cent.,  and  100  parts 
of  copper  require  176-1  parts  of  acid  of  66°  B,  to  make  362 '8  parts  of 
copper  sulphate.  This  proportion  of  acid  is  21-5  parts  in  excess  of  that  de 
manded  by  chemical  laws,  an  excess  which  is  accounted  for  by  the  acid  takea 
up  by  the  lead  oxide. 

It  should  be  remembered  that  the  coal  used  contains  for  the  most  part  20 — 30 
per  cent,  of  ash  ;  the  remainder  holding  8—10  per  cent.  All  of  it  has  about  8 
per  cent,  of  water. 

The  loss  amounted  to  3-10  per  cent,  gold,  0-65  per  cent  silver,  and  0-64  per 
cent,  copper.  The  gain  was  20-48  per  cent,  lead,  these  amounts,  as  before  said, 
not  representing  real  loss  or  gain,  but  the  commercial  values  of  the  materials 
treated  and  the  products  obtained. 

SUPPLEMENTARY  SERIES. 

Among  those  operations  which,  in  the  early  part  of  this  paper,  were  referred  to 
as  merely  supplementary  to  the  regular  course  of  the  process  are  the  Treatment 
of  the  Hard  Lead  ;  Manufacture  of  Arsenic  ;  Extraction  of  Bismuth  ;  Separation 
of  Gold  and  Extraction  of  Platinum. 

The  material  treated  in  these  operations  consists  of  :  1.  First  abatrich  from  the 
refining  of  the  lead ;  2.  Crude  arsenic  from  the  arsenic  ores  ;  3.  Litharge  and 
hearth,  containing  bismuth,  from  the  cupellation ;  and  4.  The  alloy  of  gold,  sil 
ver  and  platinum  obtained  in  cupellation. 

Dtsiluerizaiion  of  the  abstrich :  —  The  abstrich,  which  forms  about  19  per  cent, 
of  the  lead  obtained  from  the  blast  furnaces,  contains  5—6  per  cent,  antimony, 
6-7  per  cent,  arsenic,  and  0-2  per  cent,  copper.     It  is  mixed  with  3-4  per  cent 
coal,  and  heated  in  a  reverberatory  furnace.     By  this  method  a  small  quantity  of 
the  abstrich  is  reduced  to  lead,  which  is  much  rcher  in  silver  than  the  part  of 
the  abstrich  which  remains  unreduced.     The  products  are  : 
Lead,  which  goes  to  the  lead  treatment. 
Desilvered  abstrich  =0001  per  cent,  silver,  8  per  cent,  antimony,  7  per  cent. 

arsenic,  and  0-17  per  cent,  copper  ;  to  treatment  of  hard  lead. 
Fusion  for  hard  lead: — This  desilvered  abstrich  is  charged  ir»  a  shaft  furnace, 
the  charge  being  as  follows  : 

Charge  :— 300    Desiivered  abstrich. 

25    SI  »g  from  fusion  for  lead. 
5    Fluor  spar. 
Products  : 

Hard  lead=0-01  per  cent,  silver,  9 — 14  per  cent,  antimony,  3  per  cent,  arsenic, 

and  0  -4  per  cent,  copper.     To  refining. 
Abstrich  scoria=15  per  cenf.  lead. 

Treatment  of  absti'ich  scoria :— It  is  fused  again  with  25  per  cent  slag  from  the 
fusion  for  !•  ad,  and  5  per  cent,  fluor  spar.  The  products  are  hard  lead,  which 
is  added  to  that  obtained  in  the  last  operation  ;  and  2d,  abstrich  scoria,  which  is 
sent  to  the  fusion  of  matte. 

Hefming  of  Hard  Lead  : — The  hard  lead  obtained  in  the  last  two  fusions  is  re 
fined  in  a  reverbera'ory.  Arsenic  and  copper  are  more  easily  oxidized  than  lead 


FREIBEEG.  77 

and  antimony,  and  two  products  are  c-btaim  d,  one  rich  in  the  former,  and  the 
other  in  the  latter  metals.     These  products  are  : 

1.  Refined  hard  lead=9— 14  per  cent  antimony  2  per  cent  arsenic,  0-15  per 

cent,  copper.     To  poling. 

2.  Scraps=12  per  cent,  antimony,  4  per  cent,  arsenic,  and  9  per  cent,  copper. 

This  is  reduced  to  metal  by  fusion  with  25  per  cent  lead  scoria, 
and  5  per  cent,  fluor,  in  a  shaft  furnace. 

Poling  of  Hard  L&id: — This  operation,  by  which  th*  amount  of  arsenic  is  still 
further  reduced,  consists  of  plunging  green  wood  into  the  melted  lead  contained 
in  a  Pattinson  kettle.  The  result  is  : 

1 .  Lead  scraps. 

2.  Marketable  Hard  lead=9— 15  per  cent,  antimony,  1-2— 1-8  per  cent  arsenic, 

0-15  per  cent,  copper. 

The  object  of  these  repeated  operations  is  to  separate  the  arsenic  and  obtain  a 
lead,  the  hardness  of  which  sh  .11  be  due  u^ainly  to  antimony,  as  this  is  the  con 
stituent  which  makes  this  impure  lead  valuable. 

Manufacture  of  Arsenic.  Refining  :— The  production  of  commercial  arsenic  from 
arsenical  residues  of  the  sulphuric  acid  process,  and  from  flue  dust,  wap  men 
tioned  in  treating  of  the  preliminary  operations,  for  the  reason  that  these  pro 
ducts  are  mixed  with  the  ores  of  the  metal,'  and  the  two  classes  of  operations  are 
inseparable.  Therefore  to  that  description  remains  to  be  added  c»nly  the  process 
of  refining,  It  is  only  the  arsenic  made  from  ores  that  r  quires  *efining,  the 
product  obtained  from  the  flue  dust  being  already  sufficiently  pure.  The  former 
is  refined  by  redistillation  in  closed  kettles.  These  kettles  must  bo  m^de  of  an 
iron  containing  as  little  carbon  as  possible,  since  the  carbon  will  darken  the 
glacs  by  reducing  a  part  of  the  arsenious  acid  to  a  lower  degree  of  oxidation. 
The  kettles  serve  for  150  charges,  though  made  very  thin.  There  are  two  setts, 
each  containing  5  kettles  ;  the  labor  amounts  to  1  man  to  each  sett  Yellow  arse 
nic  is  made  from  white  by  adding  a  small  quantity  of  sulphur.  The  intensity  of 
color  depends  upon  the  proportion  of  sulphur,  and  the  quantity  of  the  Litter  is 
usually  2  per  cent 

Ihe  Extraction  of  Bismuth :— Only  a  very  small  part  of  the  ore  contains  bismuth 
in  sufficient  quantity  to  warrant  any  payment  for  the  metal.  But  minute  quanti 
ties  so  small  as  to  escape  the  assayer,  or,  at  all  events,  too  small  to  be  worth 
reckoning  in  the  price,  are  found  in  much  of  the  ore.  The  bismuth  is  reduced 
like  the  lead,  and  follows  that  metal  in  all  the  manipulations  up  to  cupella'ion. 
It  is,  however,  more  difficult  to  oxidize  than  lead,  but  less  so  than  silver.  The 
first  portions  of  lead  oxidized  in  the  cupel  furnace,  therefore,  contain  no  bis 
muth,  but  when  the  lead  is  enriched  to  about  50  pf-r  cent  silver,  the  bismuth 
also  begins  to  oxidize,  and  is  found  in  the  litharge  and  hearth. 

These  produc  s  are  placed  in  large  earthen  jars,  of  10  cubic  feet  capacity,  and 
treated  with  diluted  hydrochloric  acid,  the  proportions  being  300  Ibs.  litharge 
and  hearth  to  120  Ibs.  acid.  The  acid  remains  5- -6  hours,  or  until  the  beat 
arising  from  the  chemical  action  subsides.  The  jar  is  then  filled  up  with  cold 
•water  and  the  contents  well  stirred,  a'ter  which  they  are  suffered  to  rest  for  12 
hours  and  the  clear  liquid  is  then  drawn  oft  by  mtans  of  a  syphon,  into  a  tank 


78  FREIBERG. 

holding  50  cubic  feet  This  tank  is  filled  up  with  cold  water,  which  throws  down 
basic  bismuth  chloride  hydrate. 

The  residues  are  treated  9  or  10  times  with  quantities  of  acid  decreasing  from 
20  to  5  Ibs.,  and  the  liquor  is  as  before  drawn  off  into  the  large  tank. 

The  basic  bismuth  chloride  is  fused  in  iron  crucibles  With  soda  carbonate,  coal 
and  quartz.  In  1868  the  production  of  bismuth  was  about  44,000  Ibs.,  worth 
nearly  $3  25  a  pound.  The  direct  cost  of  manufacture  was  only  65  cents  a 
pound,  not  counting  in  the  extra  amount  of  cupel  hearth,  which  is  produced  by 
dividing  the  cupellation  into  two  operations. 

The  separation  of  gold  and  platinum  was  included  in  the  treatment  of  the  sil 
ver.  These  operations  do  not  differ  from  the  ordinary  methods,  and  hardly 
come  withiu  the  province  of  this  paper,  which  is  intended  to  exhibit  Freiberg  as 
a  lead  and  copper  producing  establishment. 

In  reviewing  the  processes  in  use  at  Freiberg,  it  is  evident  that  with  all  their 
excellences,  some  of  them  have  great  defects.  Many  of  the  lesser  operations  evince 
an  amount  of  skill  and  of  scientific  ingenuity  which  is  rarely  met  with.  But  on 
the  other  hand,  the  most  important  of  all  the  operations — the  fusion  for  lead — 
id  carried  on  in  a  way  not  to  be  commended.  One  of  the  chief  purposes  of  a 
fusion  of  ores  is,  in  nearly  all  cases,  to  dispose  once  and  for  all  of  that  portion 
of  the  ore  which  is  of  no  value— the  gangue .  It  is1  of  importance  to  get  out  aa 
much  metal  at  one  fusion  as  possible,  but  it  is  of  at  least  equal  importance 
to  produce  in  the  first  operation  a  slag  which  is  sufficiently  poor  to  bo 
thrown  away.  This  is  rot  done  at  Freiberg.  The  products  from  the  fusion  of 
lead  ore  all  require  re-smelting.  That  is  inevitable  with  the  lead  and  the  matte, 
for  by  the  nature  of  the  case  both  have  valuable  constituents,  which  must  be  sep 
arated.  But  the  slag  is  re-smelted  only  because  it  has  about  5  per  cent,  of  lead, 
and  slags  are  not  usually  considered  worthless  until  their  proportion  of  lead  has 
been  reduced  to  li  per  cent.,  or  less.  If  we  assume  tlese  products  to  be  in  the 
proportion  of  28  lead,  25  matte,  and  47  slag,  we  see  that  fully  one-third  of  the 
ore  ought  to  leave  the  treatment  once  for  all  at  this  step  ;  it  should  be  thrown 
away  as  useless  slag.  The  fact  that  it  is  not  thrown  away  entails  considerable 
expense  of  fuel  ana  labor.  If  it  were  possible  to  reject  at  once  33  of  the  47  per 
cent,  of  slag,  the  saving  in  fuel  alone  would  amount  to  at  least  3  per  cent,  of  the 
original  ore. 

The  fault  of  the  operation  is  the  formation  of  a  basic  slag.  To  this  is  due  the 
retention  of  so  much  lead.  Basic  slags  are,  as  a  rule,  avoided  in  lead  smelting, 
the  slag  from  lead  works  in  all  quarters  of  the  world  having,  with  tolerable  uni 
formity,  pretty  nearly  the  composition  of  a  bisilicate.  The  composition  of  worth 
less  lead  slags  may,  as  a  rule,  be  put  at  35—40  per  cent,  silica,  and  over  40  p<  r 
cent,  iron  oxide,  the  remainder  being  bases  of  various  kinds.  In  many  works 
the  amount  of  zinc  closely  approaches  that  in  the  Freiberg  slag.  These  facts  in 
dicate  that  to  place  the'  lead  treatment  at  Freiberg  on  a  par  with  that  of  o  her 
works,  it  is  necessary  to  increase  the  proportion  of  silica  in  the  charge  without 
lowering  that  of  iron  oxide  ;  that  is,  the  slag  must  be  raised  from  a  proto-  silicate 
(nearly),  as  at  present,  to  one  that  is  nearly  a  bi-silicate.  The  problem  is  then,  Is 


FREIBERG.  7VJ 

there  any  means  of  doing  this  ?  Difficult  as  it  is  to  prescribe  means  of  working 
in  an  establishment  so  distant  as  the  great  Saxon  works,  and  daring  as  is  the  task 
of  criticizing  the  management  of  men  so  able  and  so  experienced  as  those  who 
control  it,  it  still  seems  to  me  possible  to  indicate  a  theoretical  method  of  reform 
ing  this  process.  Whether  that  reformation  is  practicable  is  a  question  of  dollars 
and  cents,  which  only  the  most  intimate  acquaintance  with  (lie  f-pecial  conditions 
of  Freiberg  can  determine. 

The  Freiberg  mines  are  situated  in  the  midst  of  a  great  field  of  gneiss,  of  which 
three  kinds  are  distinguished.  The  composition  of  these  is  given  by  SCHEEBFB 
as  follows  : 

L  II.  III.  Mean. 

Silica 65-26  70-75  75-24  70-45 

Titanic  acid 0-95  050  0-20  0-55 

Clay       14-82  13-70  12-86  1379 

Iron  oxide I      6-20  5-17  2-34  4-57 

Manganese  oxide f 

Lime 2-98  2-08  095  2-00 

Magnesia 1'88  1-07  0-36  1-10 

Potassa 3-93  334  4-86  404 

Soda 2-43  2-42  230  2-38 

Water 1-06  103  068  0-92 


99-60  10006  99-80  99-80 

Here,  then,  we  have  a  substance  capable  of  supplying  the  needed  silica.  But 
if  this  alone  were  added  to  the  charge,  the  amount  of  iron  would  be  decreased, 
and  the  average  given  by  KASTand  BKAUNING  for  the  Mulduer  slag  (40  per  cent, 
iron  oxide)  is  already  as  low  as  it  ought  to  be.  Iron  must  be  added  in  some 
form,  and  probably  the  cheapest  supply  could  be  obtained  at  the  iron  works  in 
the  neighborhood  of  Freiberg.  Both  puddU-  and  reheating  slag,  can  be  had  and 
in  quantity  sufficient  to  satisfy  the  demands  even  of  works  that  treat  25,000 — 
30,000  tons  of  ore  a  year.  This  material  can  be  had  by  paying  the  expense  of 
removal,  which,  from  Camsdorf,  would  be,  delivered  at  Freiberg,  about  $1  a  ton, 
There  are  other  works  nearer  Freiberg,  from  which  the  same  slag  could  probably 
be  obtained  at  less  cost. 

At  present  a  large  amount  of  slag  from  the  same  operation  is  smelted  with  the 
ore.  It  yields  nothing,  for  it  leaves  the  furnace  with  just  as  much  lead  as  it  had 
when  it  entered.  But  it  makes  the  fusion  easier,  and  also  regulates  the  run  by 
diluting  any  impurity  in  the  ore— as  an  exceptional  amount  of  zinc  oxide.  It 
this  charge  of  slag  were  entirely  or  partially  replaced  by  a  proper  Amount  of  the 
gneiss  and  the  iron  slag,  the  composition  of  the  charge  could  be  regulated  at 
will  and  without  increasing  the  amount  of  material  treated.  Let  us  see  what  the 
proper  proportion  would  be. 

The  mean  composition  of  the  reheating  and  puddle  slag  may  he  taken,  in  the 
absence  of  analyses,  at  60  iron  oxide  and  40  silica.  Assuming  that  it  is  desired 
to  make  a  lead  slag  containing  38  silica  and  45  iron  oxide,  the  amount  of  the  two 
fluxes  necessary  to  transform  100  parts  of  the  present  Muldner  slag  into  a  slag  of 
the  new  composition  is  the  following  : 


80  FREIBERG. 

Muldner  slag.  Gneiss.  Iron  slag. 

100  parts.  20  parts.  85  parts.  Total. 

Silica  ............  31  14  34  79 

Iron  oxide  .......  41  1  51  93 

Other  bases  ......  28  5  33 

205 

These  melted  together  would  give  a  slag  containing,  in  round  numbers,  silica 
38-5,  iron  oxide  45-3  and  other  bases  16-2  per  cent.  According  to  EAST  and 
BBAUNING,  100  parts  of  ore  and  matte  in  the  lead  process  yield  about  25  lead  and 
23  matte.  The  slag  must  therefore  amount  to  about  50  per  cont.  of  the  ore  and 
matte  in  the  charge.  Calculating  the  amount  of  the  proposed  fluxes  to  be  add  >d 
to  100  parts  of  lead  ore,  roasted  pyrites  and  matte,  as  usually  charged  at  the 
Mnldner  works,  we  have  the  following  quantities  required  : 

New  charge.  Old  charge. 

Muldner  ore,  etc  .....................  100  100 

Gneiss  ..............................  10 

Reheat,  and  pud.  slag  ................  43 

Slag  from  same  operation  .............  10  60-  75 

In  this  estimate,  which  is  not  meant  to  be  exact,  no  account  has  been  taken  of 
the  basic  fluxes  —limestone  and  fluor  spar—  now  added  to  the  charge,  and  which, 
of  course,  would  be  useless  in  the  new  charge.  The  removal  of  these  would  de 
crease  to  some  extent  the  amount  of  gneiss  required. 

It  is  well  known  that  the  fusion  of  raw  fluxes  costs  more  fuel  and  requires  a 
higher  temperature  than  that  of  fluxes  which  have  already  been  melted.  Bat  in 
the  proposed  charge  the  am  unt  of  gneiss  is  too  sma  1  (7  per  cent,  of  the  whole 
chaige,  or  1  ss)  to  alter  the  present  conditions  of  the  furnace  materially.  It  ia 
<juice  probable,  in  fact,  that  the  redur  tion  of  the  zinc  oxide  in  the  slag  by  one- 
third,  and  the  production  of  a  more  fusible  slag,  would  fully  neutralize  the  dis 
advantage  of  smelting  down  the  small  quantity  of  raw  flux  required. 

One  of  the  greatest  difficulties  met  with  at  Freiberg  is  the  amount  of  zinc 
present  in  the  charge.  Care  hr,s  to  be  taken  to  manage  the  previous  roasting, 
and  the  composition  of  the  shaf  fuvnnce  charge,  so  that  only  a  part  of  the  zinc 
shall  pass  into  the  slag  and  part  into  the  matte.  When  the  amount  of  zinc  oxide 
is  right  the  old  slag  repassed  has  no  effect  upon  it,  for  it  contains  just  as  much 
of  the  zinc  oxide  as  the  charge  has.  But  tbe  addition  of  fresh  material  would  be 
of  grfat  advantage,  for  it  would  take  up  its  share  of  the  zinc  and  thus  lower  the 
percentage  in  the  whole  amount  of  slag.  If  tbe  slag  from  100  ore,  without  gneiw* 
and  iron  slag,  contains  10  per  cent,  of  zinc  oxide,  that  made  from  the  same  ore, 
with  an  addition  of  53  parts  of  those  fluxes,  would  contain  only  about  65  per 


A  slag  of  this  kind,  formed  according  to  the  principles  which  have  been  proved 
in  numberless  works,  and  containing  a  not  excessive  amount  of  zinc,  ought  to  be 
sufficiently  poor  in  lead  to  be  at  once  thrown  away.  In  |froof  of  this,  and  as  an 
indication  of  what  resulte  spring  from  comparatively  slight  changes  in  the  com 
position  of  slags,  I  will  cite  again  the  analyses  of  tLe  lead  slag  from  the  first 
matte  fusion,  as  it  is  thrown  away,  at  the  Mulduer  and  Halsbrtieke  works  : 


FREIBEllG.  81 

Muldner.  Halsbriicko. 

Silica 29-7  34.1 

Zinc  oxirte  85  7-6 

Leudoxi-ie 2-5  1-0 

Silver 00025  0-0015 

Lead  oxide  in  previous  ore  slag. ...  5'7  1*37 

The  HaTsbriicke  slag,  it  will  be  observed,  has  about  the  composition  of  tho 
ideal  slag  proposed  above. 

The  Freiberg  metallurgists  may  have  some  occult  reason  for  smelting  their  ore 
twice  over.  It  is  not  to  b«  supposed  that  with  such  excellent  materials  for  flux 
about  them  they  have  considered  themselves  forced  to  the  course  they  have 
taken.  But  what  those  reasons  are  no  traveller  has  yet  discovered.  The  Frei 
berg  works  are  a  splendid  example  of  the  success  with  which  the  products  of  a 
large  mining  district  may  be  treated  in  one  or  two  works  ;  and  the  explanation 
of  the  faulty  lead  process  has  usually  been  sought  for  in  the  diversity  and  diffi 
culty  of  the  ores  subjected  to  it.  That,  however,  as  before  remarked,  cannot  bo 
the  case,  and  it  is  to  be  hoped  that  among  the  valuable  treat  ses  on  metallurgy 
which  occasionally  come  from  the  great  mining  town  of  Saxony,  there  will  som,e 
clay  be  one  which  will  let  the  outer  world  into  the  secret  of  the  present  ^y  item. 
At  present  Freiberg  may  fairly  be  said  to  be  pursuing  one  path  and  the  rest  of 
the  world  another.  The  reasons  lor  a  course  so  singular  must  lie  either  in  gen 
eral  principles  or  in  special  conditions  of  the  place  ;  if  the  former,  it  might  aid 
the  cause  of  mining  in  the  world  to  know  what  these  principles  are. 


The  Lead  and  Silver  Works  of  the  Hartz 
Mountains. 

The  mining  region  of  the  Hartz  mountains*  is  second  in  importance  to  that  of 
Saxony  alone.  Indeed,  if  the  Mansfield  copper  mines  are  added  to  the  silver,  lead 
and  copper  mines  of  the  Upper  Hai'tz  we  have  a  district  which  is  in  every  respect 
— extent,  value  of  product,  number  of  workmen  and  intelligent  methods  of  work  — 
the  equal  of  any  other  similar  region  in  the  world.  The  subject  of  the  present 
paper  is  the  smelting  operations  at  Clausthal,  Lautenthal  and  Alteuau.  In  former 
times  the  "Upper  Harlz"  was  a  name  given  to  the  works  at  Clausthal,  Lanten- 
thal,  Altenau  and  Andreasberg,  each  of  which  had  a  completely  furnished  smelting 
establishment  where  argentiferous  lead  ores  could  be  resolved  into  merchantable 
lead,  silver  and  copper.  When  the  district  passed  into  the  hands  of  the  Prussians 
in  consequence  of  the  war  of  18G6,  changes  were  made  which  placed  the  region 
very  much  higher  than  it  had  ever  been  in  the  sc  le  of  importance.  The  mines 

*  Changes  have  followed  each  other  so  rapidly  in  the  Hartz  that  almost  every  year 
has  brought  out  some  new  process  or  important  modification  of  old  methods.  Tho 
above  notes,  therefore,  though  based  on  personal  observation,  have  been  mainly  drawn 
from  the  writings  of  KOCH,  WEDDING  and  BR^SUNINQ  and  KUHLEMANN.  With  the 
exception  of  Dr.  WEDDING  all  of  these  gentlemen  are  actively  engaged  in  the  woiufl 
they  have  described. 


82  CLAUSTHAL. 

were  worked  more  vigorously,  aad  plans  were  laid  out  for  increasing  the  amount 
of  ore  treated  to  400,^00  centners  or  20,000  tons  (of  2,000  Ibs.)  per  year.  The 
work  of  the  several  establishments  was  redistributed,  and  fundamental  changes 
v  ere  made  in  nearly  every  branch  of  the  treatment.  Clausthal  was  made  an 
establishment  chieftly  for  the  treatrn  nt  of  the  or?,  Lautenthal  for  the  separa 
tion  o  the  silver  from  the  rich  lead,  and  Altenau  for  the  copper  process.  Andreas- 
berg  alone  on  account  of  the  peculiarly  rich  arsenical  ores  found  there,  retained 
it-i  old  works,  sending,  however,  all  its  copper  matte  to  Altenau.  While  these 
changes  were  in  contemplation  the  introduction,  first  of  the  Rachette,  and  then 
of  the  Kast  iurnace,  compelled  some  delay  in  order  to  study  the  performance  of 
the  new  apparatus,  and  though  years  h*ve  passed,  the  alterations  are  haidly  yet 
fully  carr'ed  out. 

THE  WORKS  AT  CLAUSTHAL. 

First  in  the  series  comes  Clausthal  where  the  ore  is  run  down  to  metallic  lead 
and  copper  matte.  The  process  in  use  is  one  which  was  invented  at  Clausthal, 
und  wtach  though  often  derided,  has  probably  had  move  influence  upon  the 
wueltii  g  of  galena  ores  throughout  the  world  than  any  other.  It  is  the  method 
known  as  precipitation  Galena,  which  is  the  main  constituent  of  the  J-  artz 
ores  consists  of  lead  and  sulphur.  In  all  the  works  hitherto  described  in  these 
notes  the  sulphur  has  be-ii  removed  chiefly  by  combining  it  with  oxygen  — 
roasting.  At  Clausthal  iron  is  used  instead  of  oxygen.  At  first  the  metal  was 
used  direct,  i>ut  it  was  afterwards  found  that  a  silicate  rich  in  iron  oxide  served 
not  only  as  wel  but  better  than  the  metal  itself,  and  inasmuch  as  there  were 
large  stores  of  such  silicate  containing  nmall  amounts  of  copper  and  silver  which 
could  be  had  for  the  mere  cost  oi  transportation,  the  discovery  was  one  of  great 
importance.  Finally  another  modification  was  made  which  now  forms  the 
existing  mode  of  treatment. 

One  of  the  fundamental  differences  between  the  removal  of  sulphur  by  oxygen 
and  by  iron  is  th.tt  in  the  former  case  the  product  is  volatile  and  passes  directly 
out  of  our  hands  as  a  gas,  while  in  the  latter  it  is  a  solid,  called  matte  If  it 
were  possible  to  produce  a  matte  containing  nothing  but  iron  and  sulphur  there 
would  be  a'  solutely  no  drawback  to  the  precipitation  as  a  process  for  pure  lead 
ores,  ior  the  matte  could  be  thrown  away  and  the  sulphur  thus  removed  from  the 
process.  But  a  matte  produced  by  smelting  lead  ores  always  contains  lead,  and 
if  silver  and  copper  are  also  present  these  metals  always  pass  into  the  matte  in 
quantity  sufneie  t  to  make  their  extraction  a  ne  'essity.  The  mode  of  this  ex 
traction  is  the  same  throughout  ;he  world.  There  is  no  substance  available  to 
the  metallurgist  which  will  take  the  sulphur  from  the  iron  in  the  matte  as  the 
iron  has  taken  it  from  the  lead  in  the  ore,  except  one — that  is  oxygen — and  mattes, 
therefore,  are  everywhere  roasted.  The  oxidation  of  the  sulphur  is  accompanied 
by  oxidation  of  the  iron,  and  as  this  is  the  first  step  toward  the  formation  of  a 
silicate,  it  is  only  necessary  to  melt  the  roasted  matte  with  quartz  in  order  to 
remove  the  oxidised  iron  in  the  form  of  a  slag.  This  treatment  of  the  matte  is 
a  Bc-rioas  item  of  expense. 

The  cer.niuty  that  the  matte  will  contain  the  copper  is  by  no  menus  an  evil. 
On  the  contrary,  were  it  not  bo  the  metallurgist  would  bepuzzled  to  know  how  to 


CLAUSTHAL.  83 

his  copper  from  the  lead.  The  whole  treatment  of  sulphides  containing] 
copper  is  based  upon  the  chemical  fact  that  copp<-r  and  sulphur  will  in  all  cases' 
unite  in  the  furnace,  provided  the  amount  of  sulphur  present  is  not  sufficient  for 
both  the  iron  and  the  copper  ;  the  former  can  be  removed  by  the  addition  of 
quartz,  a  slag  being  the  result.  This  action  is  so  certain  that  the  metallurgist, 
who  has  a  copper  matte  which  has  been  roasted  "dead,"  that  is,  has  had  all  the 
sulphur  removed  and  the  copper  and  iron  completely  transformed  to  oxides  would 
have  no  hesitation  in  charging  it  in  a  furnace  with  an  iron  pyrites  containing 
only  quartz,  iron  and  sulphur,  and  no  copper  at  all.  The  result  in  all  cases  is 
that  the  copper  unites  with  the  sulphur  and  the  quartz  with  the  iron  oxide. 

In  the  Hartz,  the  treatment  of  ore  and  nutte  forms  one  operation.  Instead  of 
melting  the  ore  with  a  si  >g  rich  in  iron,  to  remove  the  sulphur,  and  melting  the 
roasted  matte  with  another  sla,^  ri<-.h  in  silica,  to  remove  the  iron  oxide,  they 
combine  the  two  processes  and  melt  the  ore  and  the  roasted  matte  together.  As 
the  ore  contains  both  quartz  and  sulphur  the  oxidized  iron  passes  partly  into 
the  slag  with  one  and  partly  into  a  new  matte  with  the  other.  The  matte, 
therefore,  makes  a  continuous  round,  being  roasted  and  re-smelted  with  the  ore 
five  or  six.  times. 

It  is  easy  to  see  that  this  is  really  no  more  nor  less  than  a  roasting  process, 
though  the  roasting  is  transferred  from  the  ore  to  a  matte.  There  are  two  ad 
vantages  to  be  obtained  from  this  treatment.  One  is  the  less  bulk  of  the  matte 
to  be  roasted,  amounting  to  not  more  than  half,  or  at  most,  two-thirds  the  oro. 
The  other  is  that  the  sulphides  of  iron  are  in  all  cases  much  easier  and  che  per 
to  roast  than  the  sulphides  of  lead.  They  contain  more  sulphur,  require  less 
fuel,  and  present  less  liability  to  sintering  and  imperfect  roasting.  Other  im 
portant  advantages  are,  first,  that  the  lead  and  silver  having  been  mostly  re 
moved,  the  loss  from  volatilization  is  much  less,  and,  second,  that  the  sulphur  in 
the  matte  can  be  utilized  by  making  sulphuric  acid  from  it,  while  the  ore  id 
useless  for  that  purpose  because  it  contains  so  little  sulphur. 

The  ore  treated  at  Clausthal  had,  according  to  KOCH  (1869),  the  following 
composition  : 

71.676  per  cent,  lead  sulphide  or  02,07  lead. 

0.945  do  copper  sulphide  0.75  copper. 

1.880  do  zinc  sulphide. 

0. 537  do  antimony  sulphide. 

1.410  do  iron  sulphide. 

0.113  do  silver  sulphide  or  0.003  silver. 

4.139      do  iron  carbonate. 

0.150  do  alumina 

2.380  do  lime  carbonate. 

1.460  do  baryta  sulpha'.O. 

0.075  do  magnesia. 

15.235  do  silica. 

This  is  a  mixture  of  ores  obtained  from  a  great  nnmVr  of  mines,  anfl  ttie 
occasional  preponderance  of  ore  from  some  one  mine  will  sometimes  a  ter  the 
composition  of  the  charges  smelted  for  a  few  days.  The  usual  composition 
of  the  charge,  as  at  first  established,  may,  however,  be  ascertained  from 
the  following  quantities  which  were  smelted  during  the  months  of  July, 


84  CLA.USTHAL. 

August,  and  September,  18G6.  The  quantities  are  hundredweights  of 
110  English  pounds.  The  proportions  of  hearth  and  rich  litharge  are  worth 
noticing,  for  the  Claustbal  works  us^  the  German  cupel  hearth,  and  these  are 
therefore  the  proportions  in  which  cupel  scraps  are  produced  in  treating  a  6li 
per  cent,  ore,  by  this  method  : 

Per  ton. 

Ore 33,400  cwt  100  2000  Ib. 

Roasted  matte 17,5(35    „  524  1050    „ 

Copper  slag 22,248    „  663  1332    „ 

Slag  from  same  op  era  tion55, 5  42    ,,  1GG£  3332   ,, 

Cupel  hearth 1,112    ,,8  6    „ 

Bich  litherage 624    „  2  3    „ 

Scraps 262    „  03  lj    „ 

Days'  labor  (12  h)  1,002  3i  3-5ths  day 

Coke 14,964    ,. )  ,„  ,  r  q .,  ,. 

Charcoal.. 810    „  f  JM  lb' 

This  is  therefore  an  expense  of  a  three-fifths  of  a  day's  labor,  and  944  pounds  of 
coke  per  ton  of  ore.  The  cause  of  this  large  expense  of  fuel  is  the  use  of  so 
much  flux,  amounting  to  284  per  cent,  of  the  ore.  This  excessive  proportion  of 
flux  is  one  of  the  peculiarities  of  the  Hartz.  Nowhere  el^e  is  it  used  in  such  pro 
fusion,  but  innumerable  attempts  to  reduce  it  there  have,  without  exception, 
failed.  When  slag  is  used  as  a  precipitating  material  a  bulky  charge  is  the 
necessary  result,  but  even  when  metallic  iron  was  the  precipitating  agent,  121 
per  cent,  of  i-lag  was  added  to  the  ore.  The  causes  of  this  peculiarity  have  never 
been  published. 

Considerable  changes  have  been  made  in  the  above  proportions,  the  chief  of 
which  was  to  cut  down  the  amount  of  slag  from  the  same  operation  rep;\ssed,  to 
75  and  70  per  cent,  which  reduced  the  flux  and  precipitating  material  to  190  per 
cent,  of  the  ore.  The  charge  at  one  time  was  made  up  of  100  ore,  50  roasted 
matte,  70  copper  slag  and  70  lead  slag,  smelted  with  about  43  coke.  It  was 
found,  however,  that  with  these  proportions  the  matte  became  so  rich  in  copper 
as  to  part  with  some  of  that  metal  to  the  lead.  The  roasted  matte  obtained  from 
ore  smelted  with  slags  alone  contained  3  per  cent,  of  copper,  which  rose  to  8  and 
even  9  per  cent  by  re-fusion  with  ore  and  the  lead  instead  of  0. 3  per  cent. ,  as 
formerly,  contained  0.6  to  0.7  per  cent,  of  copper.  This  increased  the  difficulty 
and  cost  of  desilverization,  and  the  proportion  of  roasted  matte  was  diminished 
to  28  per  cent,  of  the  ore.  The  exact  composition  of  the  new  charge  I  have  not 
been  aUe  to  obtain,  but  it  is  probably  about  the  following  :  Ore  100,  roasted 
matte  28,  slags  150-170.  After  the  change  the  copper  in  the  matte  sank  to  5£ 
per  cent.,  and  in  the  lead  to  0.4  and  0.5  per  cent. 
The  products  dur  ng  the  above-mentioned  three  months  were 

From  100  Ore 

Lead,  21,380  cwt 65* 

Matte.24,253    , 72f 

The  three  methods  of  treatment  successively  used  at  Clanslhal,  bare  given  the 
following  results  in  regard  to  product : 

"With  metalic  iron.          With  copper  slag.          "With  roasted  matte, 

Lead,  54 65  65i  and  05 

Matte,44 55  72-}  aud  66 


CIAUSTHAL.  85 

The  simplicity  of  this  precipitation  method  would  recommend  it  in  nearly  all 
cases  were  it  not  for  the  large  increase  of  cost  which  results  from  using  so  much 
flux,  and  the  production  of  so  much  matte.  The  practice  of  adding  puddle  and 
reheating  cinder  to  lead  ores  in  the  shaft  furnace,  is  now  so  common  that  tho 
business  of  lead  smelting  has,  in  some  regions,  almost  become  auxilliary  to  tho 
manufacture  of  iron.  Under  these  circumstances  it  is  always  a  question  whether 
the  operation  of  roasting,  costly  in  plant  and  in  practice,  cannot  be  supplanted 
by  merely  increasing  the  proportion  of  iron  flux,  and  re-charging  the  matto 
formed.  In  those  cases  where  ores,  pure  in  Lad  and  rich  in  silver,  are  smelted 
for  the  silver  they  contain,  and  there  is  therefore  no  desire  to  keep  the  lead  pure, 
it  seems  probable  that  this  method  would  be  found  decidedly  advantageous. 

The  lead  obtained  is  not  pure.  Analyse*  of  thelead  and  matte  given  by  KOCH, 
are  as  follows  ;  although  obtained  by  the  former  precipitation  with  copper  slog, 
they  fairly  represent  the  same  products  from  the  present  process. 

Lead.  Matte. 

Antimony 0.613  0.350 

Copper 0.276  4.392 

Iron 0.002  55.720 

Zinc 0.008  1.125 

Silver 0.127  0.029 

Lead 98.969  7.984 

Sulphur 29.546 

100  99.146 

The  slag  is  maintained  with  great  regularity  between  a  proto-and  a  bi-silicate.' 
It  is  rich  in  iron,  very  poor  in  lead,  and  can  be  thrown  away  at  once.  OnJy  a 
very  small  portion— that  which  solidifies  in  the  fore  hearth — must  be  re-chargyd 
on  account  of  grains  of  lead  and  matte  mechanically  contained  in  it.  Tho  fol 
lowing  is  an  analysis  of  this  ordinary  slag  : 

Silica ,43.60  Magnesia 1.56 

Iron  oxide 31.68  Lead  oxide 0.70 

Alumina 15.50  Silver  oxide 0.000087 

Lime 6. 50 

99.54087. 

The  furnaces  in  which  the  fusion  takes  place  are  of  two  kinds,  the  round  or 
Kafit  furnace,  and  the  Rachettc.  The  round  furnaces  at  Clausthal  form  an 
interesting  series  of  experiments  in.  the  most  recent  progress  of  lead  metallurgy. 
The  principles  which  were  introduced  into  the  construction  of  lead  furnaces  by 
the  English  in  Spain,  30  years  ago  or  more,  and  have  been  modified  by  PFANDEB- 
HEIPKX,  PILTZ,  and  others;  have  also  made  their  way  to  Clausthal.  Five  round 
furnaces  of  various  dimensions  and  construction  are  found  there.  One  of  tho 
peculiarities  of  the  Clausthal  system  of  smelting  is  that  the  ore  must  be  in  tho 
form  of  powder,  and  this  formerly  caused  so  much  dust  that  from  5  to  8  per 
cent,  was  taken  from  the  dust  chambers.  This  gave  rise  to  a  very  unusual  moda 
of  building  the  furnaces.  A  row  of  heavy  brick  piers  was  built,  and  the  inter 
vening  spaces  arched  over.  On  these  arches  was  raised  a  line  of  dust  chambers, 
which  not  being  intended  to  condense  volatilized  lead,  but  merely  to  give  tha 


CLAUSTHAL.  87 

fine  dust  opportunity  to  settle,  could  be  placed  immediately  over  the  nm  ices. 
l>ut  tLe  result  o'  this  mode  of  construction  was  to  place  a  limit  to  the  sizo  of  the 
furnace  which  could  be  built  between  two  of  the  piers,  and  when  the  nev/  doctrines 
in  furnace  building  began  to  spread  Mr.  K.VST,  d  rector  at  the  smelting  works  at 
Oausthal,  had  to  experiment  to  ascertain  what  were  the  smallest  diameters  that 
would  prevent  the  dust  from  flying  out  of  his  furnaces.  At  first  a  furnace  3 
feet  in  diameter  at  the  tuyeres  and  4  feet  at  the  top  was  built,  but  the  amount  of 
duct  was  still  excessive.  Then  the  diameter  at  the  mouth  was  increase.!  to  4£ 
feet,  which  caused  a  reduction  of  the  flae  dust  to  2  per  cent.  The  slowness  of 
the  ascending  current  of  gas  in  the  upper  part  of  the  furnace  also  affects  very 
favorably  the  utilization  of  the  cok  .  and  the  amount  of  material  run  through  in 
a  day.  The  following  table  gives  a  comparison  of  the  four  round  furnaces  v.ith 
a  Ruchette.  All  of  the  round  furuaccs  have  the  same  dUmeter  at  the  tuyeres,  3 
foot,  and  the  same  height,  21  feet.  The  diameter  of  the  Tlachctto  at  the  tuyeres 
i  i  also  3  feet; 

Diameter  at        Coke  per  ICO  ore.         Flue   dust.  Time  to  sm  It 

mouth.  11, (r>0  Ibs.  ore.* 

No.  1 4ft.  2in.  45.39  2.8  per  ccn1.  73.2  hours. 

No.  2 4ft.  Sin.  41.85  2.1         "  71.8     " 

No.  3.... 6ft.  Oin.  41.74  1.7        '  71.2     " 

No.  4 6ft  3in.  41. G2  1.1         "  C'J.2     " 

Hachette..4ft.  9in.  413  1  "  93.2     " 

The  round  furnaces,  called  also  Kast  furnaces,  after  the  Director  of  the  works, 
do  not  differ  from  the  general  type  of  modern  lead  furnaces,  except  that,  being 
built  between  piers  of  masonry,  they  are  not  approa?hable  on  all  sides.  They 
are  made  with  fore  hearth,  over  the  dam  of  which  tho  slag  runs  without  cessation. 
The  number  of  tuyeres  ranges  from  4  to  7. 

Like  so  many  lead  furnaces  in  Europe,  these  are  built  of  ordinary  red  brick, 
only  a  few  fire  brick  being  placed  around  the  tuyeres,  and  these  are  in  fact  often 
omitted.  These  furnaces  have  made  an  uninterrupted  campaign  of  2  or  3  years, 
a  result  which  is  due  to  the  accuracy  wi*h  which  the  composition  of  the  slag  is 
calculated  and  maintained.  The  ore  and  flux  are  spread  out  in  layers  upon  each 
other  on  tho  floor  at  tho  furnace  mouth,  and  charged  equally  over  the  whole 
surface  of  the  iurnace,  the  coke  being  spread  out  in  the  same  way.  The  pressure 
of  air  is  10  to  12  lines  of  mercury. 
figures  12  to  14  givo  sections  of  the  Kast  furnaces.  The  dimensions  of  one  are 

Height 20ft 

Dia  fcter  at  mouth 5ft. 

Do.  at  tuyeres 3ft 

Do.    at  sole 2ft.  4in. 

Number  of  tuyeres 4 

1  re^sure  of  blast .11 — 14  lines  of  mercury. 

They  are  open  at  the  month,  having  no  hopper  nor  cylinder.  The  ore  and 
coke  are  spread  evsnly  over  the  surface,  the  ore  being  thrown  from  wooden 
troughs,  and  tho  coke  from  flat  baskets.  The  charges  for  24  hours  are  always 
made  up  in  the  morning,  so  that  at  night  nothing  but  tapping  the  furnace  and 
throwing  the  slag  oil  the  slag-run  takes  place.  All  furnaces  at  Clausthal  have  a 
fore  hearth,  over  the  edge  of  which  the  slag  ruos,  passing  down  a  narrow  inclined 


83 


CLAUSTHAL. 


1 


KACIIETTE    FUJiXACE    AT    CLAVSTXAZ. 


ISSMSWiS 


CLAUSTHAL. 


89 


bank  made  of  brasque.  It  solidifies  on  this,  and  is  thrown  to  one  side  by  the 
workman  who  wields  a  two-pronged  fork.  The  lead  is  not  tapped  f  om  the  body  of 
the  turnace,  but  from  the  front  hearth  where  it  collects.  This  front  hearth  is 
formed  inside  of  an  iron  box  projecting  from  the  furnace,  and  in  the  side  of  this 
box  is  the  tap. 

In  addition  to  these  Kast  furnaces  Clausthal  possesses  a  Piltz  of  the  same 
pattern  as  those  at  Freiburg,  but  w  th  some  judicious  alteration0  in  the  method 
of  suspension.  It  is  octagonal,  24  feet  high,  4ft.  Sin.  diameter  at  the  tuyeres,  and 
6ft.  Sin.  at  the  mouth.  The  8  water  tuyeres  are  15  iaches  above  the  slag  spouts. 
It  was  attempted  to  run  this  furnace  with  a  closed  hearth,  but  outside  modifications 
do  not  seem  to  succeed  in  the  Hartz,  and  it  was  found  impossible  to  produce  a 
fusible  slag.  The  furnace  was  accordingly  narrowed  to  4ft.  2  n.  at  the  tuyeres, 
and  fitted  with  a  front  hearth.  It  is  now  in  successful  operation. 

The  Rachette  furnaces  were  for  a  long  time  the  best  that  Clausthal  possessed,  but 
they  seem  to  offer  no  advantages  over  the  round  furnaces,  while  they  are  not 
only  more  costly  to  build,  but  also  are  subject  to  a  patent  right.  Their  form  ia 


Fig.  21. 

shown  in  figures  15  to  18.  Figure  15  shows  a  vertical  section  of  the  furnace 
through  the  longer  axis  ;  fig.  16  is  a  horizontal  section,  though  the  tuyeres,  fig. 
17,  shows  the  tuyeres  in  place,  and  fig.  18  gives  a  horizontal  section  and  end  view 
of  a  tuyere. 

The  Rachette  furnace  is  a  construction  designed  to  obtain  great  capacity,  with 
out  making  the  diameter  greater  than  twice  the  throw  of  the  blast.  To  that  end 
it  is  made  rectangular,  and  long  and  narrow.  Tuyeres  are  placed  on  each  of  the 
long  sides,  and  throw  their  air  through  the  furnace  in  its  narrowest  direction; 
and  the  form  of  the  furnace  is  such  that  any  number  of  tuyeres  can  be  used  by 
merely  lengthening  the  furnace.  Usually  five  on  a  side  is  the  number.  For- 


90  IAUTENTHAL. 

nierly  the  ends  had  no  tuyeres,  but  it  having  been  observed  that  scaffolds  and 
accretions  collected  only  on  the   ends,  these   have  also    been  furnished  with 


Fig.  22. 

tuyeres,  and  with  good  effect.  There  is  a  tap  at  each  end  whieh  requires  a 
double  set  of  men  at  the  bottom.  The  main  dimensions  of  the  Altenau  Eachette 
furnace,  the  first  built  in  theHartz,  are  given  below  ;  they  have  not  been  mate 
rially  changed  in  any  of  the  newer  ones  : 

Height 19  feet    6  inches. 

V>  idth  at  tuyeres 2    ,,     11      ,, 

Width  at  top 4    ,,       6      „ 

Length 7     ,,       4      „ 

Distance  between  tuyeres 1     ,,       4      ,, 

It  is  an  excellent  furnace  and  smelts  16,500  Ib.  of  ore,  or  44,000  Ib.  of  charge 
in  24  hours  with  about  5,500  Ib.  coke.  The  increased  width  of  the  throat  keeps 
the  loss  by  dust  down  to  a  minimum,  provided  the  pressure  of  blast  does  not  ex 
ceed  10  or  12  lines  of  mercury. 

THE  WORKS  AT  LAUTENTHAL. 

The  lead  is  all  desilvered  at  Lautenthal  by  the  zinc  and  steam  process,  which, 
however,  differs  very  greatly  in  its  details  from  the  system  pursued  at  other 
works.  The  operations  in  the  process  are  : 

1.  Fusion  and  treatment  with  zinc. 

2.  Treat-merit  of  poor  lead  with  steam,  under  a  hood,  to  remove  the  zinc. 

3.  Treatment  of  the  poor  lead  with  steam  and  admission  of  air,  to  remove  the 
antimony. 

4.  Casting  the  purified  lead. 

5.  Treatment  of  the  rich  crusts,  or  alloy,  with  steam,  to  remove  the  zirc. 

6.  Cupellatiou  of  the  rich  lead  resulting  from  5,  with  addition  oi  the  rich  ox 
ides  to  extract  their  silver. 

7.  Treatment  of  the  poor  oxides. 

Treatment  with  Zinc. — The  kettles  used  are  old  Pattinson  kettles,  of  5  feet 
6i  inches  diameter  and  2  feet  10  inches  depth.  Each  holds  27,500  Ib.  of  lead, 
and  three  are  worked  together,  forming  a  battery.  The  two  .outer  kettles  are 
charged  with  27i  tons  (of  2,000  Ib.)  of  lead,  which  is  melted  down  in  about  six 
houi-s,  when  an  abzug,  or  lead  containing  enough  copper,  iron,  etc.,  to  make  its 
point  of  fusion  higher  than  that  of  pure  metal,  is  taken  off  and  cast  in 
moulds.  Each  of  the  end  kettles,  then  receives  49  i  Ib.  zinc.  The  object  of 
making  this  first  charge  so  small  is  to  concentrate  the  gold,  of  which  the  lead 
contains  a  very  minute  proportion,  in  a  small  quantity  of  silver.  It  is  a  peculi 
arity  of  the  process  that  silver  is  not  taken  up  except  in  a  small  quantity,  uutil 
the  gold  and  copper  have  been  removed.  The  result  of  this  first  charge  is  a 
crust  which  contains  all  the  copper  and  gol^,  without  being  much  riche;  in  silver 
than  the  original  work  lead.  In  spite  of  this  decided  concentration,  the  silver 
made  from  this  crust  contains  only  0.12  to  0.20  per  cent,  of  gold,  fctill  the  latter 
met  J  pays  for  its  separation. 


LAUTEXTHAL.  91 

When  t^ie  zine  charge  has  molted,  the  bath  is  stirred  by  two  men  at  each 
kettle  for  twenty-five  minutes,  the  stirrer  being  a  broad,  flat  and  long-handled 
iron  disc,  pierced  with  holes.  The  metal  is  then  cooled  until  a  cru-t  of  about 
14  inches  thickness  forms  on  top.  It  is  a  matt  r  of  importance  to  so  manage  the 
cooling  that  it  shall  take  place  mainly  from  the  surface,  in  order  to  prevent  the 
formation  of  a  thick  crust  on  the  bottom  of  the  kettle,  for  this  crust  would  contain 
zinc  and  silver.  To  avoid  this  the  fire  is  merely  covered  with  ashes.  Tho 
top  crust  is  thrown  into  the  middle  kettle,  and  when  this  is  completed  a  new 
charge  of  258£  Ib.  zino  is  made  to  each  outside  vessel,  and  the  fires  are  freshened. 
The  stirring  in,  cooling  down,  and  skimming  are  repeated,  and  the  last  cha!ge 
of  77  Ib.  zinc  is  then  made,  and  the  same  operation  gone  through  with.  The 
time  consumed  in  completing  a  change  is  about  as  follows  :  Drawing  abzug,  30 
minutes  ;  melting,  1 — 1£  hours  ;  total,  6-7  hours.  The  desilverization  ol  27£ 
tons  of  lead  requires  about  thirty  Lours. 

The  middle  kettle  is  now  heated,  the  bath  stirred,  cooled  and  skimmed,  the 
crust  being  a  concentration  of  the  three  crusts  taken  from  the  other  two  kettles. 
This  is  cast  in  moulds.  From  20  to  40  Ib.  of  zinc  are  added  to  the  bath,  and  the 
above  operations  are  repeated.  If  necessary,  a  second  charge  of  ziuc  is  made. 

According  to  the  above  the  zinc  charge  amounts  to  14  per  cent  of  the  lead. 
The  crusts,  do  not  contain  all  the  zinc,  but  fully  one-half  is  left  in  the  poor 
lead.  The  removal  of  this  zinc  has  been  the  most  difficult  problem  in  the  whole 
process  of  desilverization,  and  though  the  poor  lead  can  now  be  treated  without 
difficulty,  no  direct  and  simple  method  of  separating  the  zinc  from  the  ri  h  crusts 
has  yet  been  found,  unless  the  costly  mode  of  distillation  is  excepted. 

De zincing  the  poor  lead. — The  three  kettles  now  contain  poor  lead,  which  is 
deziuced  by  blowing  superheated  steam  at  15  Ib.  pressure  through  the  bath,  by 
means  of  a  bent  pipe,  two  inches  in  diameter,  running  to  the  bottom  A  sheet  iron 
hood  communicating  with  a  large  pipe  is  bolted  down  on  the  kettle  and  the  joint 
is  luted.  The  lead  is  kept  at  a  little  below  cherry  red,  and  is  steamed  for  four 
hours  to  remove  the  zinc,  and  for  tMo  hours  more  to  remove  the  antimony,  air 
being  admitted  by  opening  the  door  of  the  hood.  Inasmuch  as  the  antimony  is 
not  carried  over  with  the  rich  crust,  the  middle  kettle  is  steamed  to  remove  the 
zinc  alone.  In  this  operation  the  temperature  is  a  point  of  great  importance. 
Il  too  low,  a  longer  time  is  required,  and  the  amount  of  oxides  formed  is  in- 
cr  ased.  If  too  high,  the  kettles  are  rapidly  destroyed.  At  the  right  tempera 
ture  0-7  per  cent,  of  zinc  and  1  per  cent,  of  antimony  can  be  removed  in  the 
time  given. 

The  object  of  passing  the  steam  through  the  bath  is  to  oxidize  the  zinc,  but 
a  good  deal  of  lead  is  also  oxidized,  and  the  oxide  first  formed  is  fluid,  but  it 
gradually  becomes  powdery  nnd  "dry."  The  oxides  from  the  end  kettles  ara 
yellow,  but  those  formed  in  the  middle  kettle  are  greenish,  showing  a  prepon 
derance  of  zinc.  Perfect  dryness  of  the  oxides  is  a  sign  that  all  the  ziuc  has 
been  removed.  Other  tests  are  to  cast  a  small  assay  in  &  scorifier  from  time  to 
time,  until  no  star  forms  in  the  center  upon  cooling.  The  star  would  indicate 
the  presence  of  antimony.  The  kettle  is  also  left  expo-ed  to  the  air  a  while, 
without  steam,  after  the  oxides  have  been  removed.  If  a  clear  red  litharge  forms, 
ihe  lead  is  pure.  Another  test  for  zinc  is  to  take  a  ladle- full,  Bciapa  the  surfa-  e, 


92 


LAUTENTHAL. 


while  hot,  with  a  piece  of  wood,  and  if  the  silky  app<  arance  is  gone  the  zinc  has 
be  n  remoTed.  When  the  tests  show  the  lead  to  be  free  from  both  zinc  and  anti 
mony,  the  lead  is  ladled  into  moulds,  and  forms  the  "  Refined  Hartz  lead."  It 
is  so  nearly  pure  as  to  contain  from  99-983  to  99-987  per  cent.  lead. 

The  dezinc'mg  of  the  rich  crust  presents  more  difficulties.  The  withdrawal  of 
osygen  from  the  steam  by  the  zinc  leaves  a  gas  so  high'y  charged  with  hydrogen 
as  to  be  violently  explosive  when  the  hot  gas  conies  in  contact  with  the  air.  Jn 
dezinciiig  the  poor  lead,  the  deoxydatiou  of  the  sttam  is  quite  imperfect,  and  the 
resulting  gas  never  gives  alarming  explosions.  But  the  rich  crusts  contain  5 
or  6  per  cent,  of  zinc,  and  severe  explosions  of  the  gas  have  occurred.  These 
are,  however,  now  complete  y  prevented  by  turning  steam  direct  into  the  hood 
before  allowing  air  to  enter  it. 

The  products  now  consist  of :  (1)  refined  lead  ready  for  market ;  (2)  rch 
lead  containing  about  li  per  cent,  silver  which  is  cupelled  in  a  German  hearth. 
(3)  Poor  oxides  free  from  antimony,  and  others  containing  antimony.  The  for 
mer  are  washed  on  a  sleeping  table  which  separates  them  into  two  qualities.  Of 
these  one  consists  of  metallic  lead  and  lead  oxide,  containing  about  85  per  cent, 
of  the  metal ;  it  is  reduced  to  second  quality  metal.  The  remainder,  containing 
much  ziuc,  is  of  a  yellow  color  and  is  sold  as  paint.  The  oxides  containin  anti 
mony  are  melted  with  other  similar  products  to  hard  lead.  (4)  Rich  oxides. 
These  are  placed  upon  the  bath  in  the  cupel  furnace,  the  heat  being  raised  to  the 
highest  limit.  The  silver  passes  into  the  lead,  some  lead  being  oxidized  in  the 
exchange.  A  slag,  consisting  of  zinc  oxide,  lead  oxide  and  metallic  lead,  re 
mains  and  is  drawn  off.  It  contains  about  50  ounces  silver  to  the  ton  and  is  re 
duced  with  rich  litharge  to  metal  which  passes  a  second  time  through  the  desil- 
verization  process.  To  have  a  successful  imbibition,  or  absorption  of  silver  by 
the  lead  in  the  cupel  hearth,  it  is  necessary  to  keep  the  rich  oxides  from  being 
too  dry.  With  lead,  such  as  is  produced  in  the  Hartz — containing  38  ounces  to 
the  ton — the  oxides  are  in  the  right  proportion  when  they  form  8  to  10  per  cent. 
oi  the  desilvered  lead. 

WEDDING  and  BR.EUNNING  give  the  following  summary  of  the  results  obtained 
by  this  process  in  1869.  The  German  centner  of  110  Ib.  English  weight  is  here 
given  as  cwL 

MATERIAL  AND  PRODUCTS. 


WEIGHT. 

PERCENTAGE. 

SILVER. 

Ib. 

LEAD. 

Ib. 

SILVER. 

LEAD. 

85-389 
8-662 
2223 
0-250 
0.267 

Charged  :  22,053  cwt.  work  lend  

31GS* 
3243£ 

22,U21i 

18,8031 
1,9071 
489  ft 
654 

58| 

102-372 

Produced  :  3,525$  Ib.  crude  silver,  contain 
ing  fine  silver  

Refined  Hartz  lead  

Merchanlable  litharge  64  cwt  

Total   

3233$ 

211,315 

3921 

102-36* 
102-372 

96-791 

1-781 

98  5U2 

Various  products  not  worked  up  : 
452  cwt  

Total.  . 

LAUTENTHAL.  93 

It  is  certainly  remarkable  tint  the  intermediate  products  ftill  in  treatment, 
consisting  of  hearth,  scraps,  litharge,  abstrich,  and  impure  lead  obtained  in  li 
quating  the  hard  lead,  should  amount  to  only  22J  tons  or  1-781  per  cent,  of  the 
lead  treated.  The  second  quality  lead  is  made  from  the  washed  oxides  mentioned 
above,  the  scraps  formed  in  ladling  the  first  quality  metal  from  the  kettle  and 
other  products  free  Irom  silver.  It  is  blown  with  steam  .to  remove  the  antimony 
and  then  casf.  Its  only  impurity  is  a  small  proportion  of  copper.  The  hard 
lead  is  obtained  by  smelting  the  oxides  containing  antimony,  and  this  also  is 
blown  with  steam  to  remove  the  zinc  and  copper.  Thus  the  steam  process  is 
now  used  for  the  refining  of  all  kinds,  and  by  its  use  the  numerous  operations 
which  made  up  the  old  process  of  cupel  at  ion  and  refining  by  air  have  been  entirely 
superseded. 

In  ladling  out  the  refined  lead,  an  assay  weighing  about  £  Ib.  is  cast  for  every 
8  pigs  c.f  lead.  When  5000  pigs  have  been  cast,  these  assays  are  melted  together, 
and  some  pounds  are  cast  and  sent  to  the  laboratory  for  analysis.  The  first  of 
the  following  analyses  is  from  the  lead  produced  at  Lautenthal  in  1870  up  to  the 
month  of  August,  and  represents  20,465  pigs  or  about  1575  tons.  The  other  is 
from  1193  tons  of  lead  T  fined  at  Altenau,  where  refining  was  still  in  operation  in 
that  year.  Each  analysis  is  the  mean  of  4  nude  upon  1400  gram  in  PS  in  one  case, 
and  15UO  grammes  in  the  other.  It  is  noteworthy  that  although  refined  at  differ 
ent  and  widely  separated  establishments,  and  made  from  work  lead  of  very  dif 
ferent  composition  in  regard  to  impurity,  the  refined  lead  shows  a  difference  of 
only  4-1000  of  a  per  cent,  that  from  Altenau,  whera  the  copper  ores  and  matte 
are  worked,  showing  a  small  excess  of  impurity.  This  similarity  of  composition 
is  a  proof  of  the  method  with  which  the  operations  are  carried  out. 

Leal 99-983139  99  987560 

Copper 0-001413  (M;02022 

An-imony 0-005698  0-003335 

Bsmutk" 0-005487  0-003650 

Silver 0-000460  0000721 

Iron 0-002289  0-001229 

Zinc 0-000834  0-000776 

Niufcel 0-000680  0-000707 

100-  100- 

In  regard  to  the  bismuth  present  in  the  above,  it  is  worthy  of  remark  that  stenm 
has  no  effect  upon  this  metal,  which  remains  with  the  1-  ad.  This  circumstan-e, 
which  has  been  developed  only  within  a  few  years,  is  a  matter  of  great  impor 
tance  to  works  which,  like  Freiberg,  make  considerable  quantities  of  bismuth 
from  intermediate  products,  which  would  be  lost  were  it  not  concentrated  in 
those  products.  Pattinson-'s  process  effects  this  concentration,  and  this  is  another 
reason  why  that  system  of  concentration,  now  so  generally  rejected,  should  be 
retained  at  Freiberg.  "'. 

The  purity  which  now  distinguishes  the  Harz  >ead  has  not  been  obtained  with 
out  much  trouble  and  study.  Compared  with  the  lead  obtained  from  cupel- 
lation,  the  Pattiuson,  salt-aud-poling  and  steam  processes  have  yielded  8.  product 
which  has  shown  an  advancing  purity. 


94:  ALTENAT7. 

THE  COPPER  PROCESS  AT  ALTENAU. 

When  the  matte  is  withdrawn  from  the  ore  fusion  it  contains  about  eight  per 
cent,  copper  and  seven  per  cent.  lead.  It  is  roasted  in  a  square  kiln,  twenty 
feet  high,  four  feet  square  at  the  bottom,  and  5X^  feet  at  the  top.  The 
ma'te  is  broken  into  pieces,  1  or  U  inches  square.  Only  the  upper  part  of 
the  kiln  is  hot,  the  fire  not  sinking  below  3  feet  from  tho  mouth,  while  the  re 
maining  9  feet  serve  as  a  regenerator  td  heat  the  ascending  air,  a  process  which 
of  course  cools  the  matte.  Two  doors  at  the  mouth  are  used  for  charging  ;  two 
others  are  placed  two  feet  under  them  for  the  purpose  of  loosening  the  charge, 
and  finally  there  are  two  more  on  a  level  with  the  sole,  to  allow  for  discharging. 
With  good  management  of  the  draft  the  kiln  burns  for  weeks.  If  too  much  air 
enters,  the  combustion  may  be  sufficiently  strong  to  sinter  the  charge  together, 
or,  allowed  to  increase  still  further,  enough  cold  air  to  put  the  fire  out  may  enter. 
*]  he  matte,  \vhich  contains  about  22  per  cent,  of  sulphur,  is  reduced  to  12  per 
cent,  by  two  roastings  in  the  kiln.  The  kilns  are  connected  with  sulphuric  acid 
chambers,  and  no  difficulty  has  occurred  in  utilizing  the  sulphur  of  "the  matte 
in  this  way.  After  the  second  kiln  roasting,  the  matte  is  piled  in  a  low  heap 
and  roasted  with  the  addition  of  brush  fuel  to  6  per  cent,  sulphur.  Jt  is  then 
sm  Ited  in  low,  square  furnaces,  about  9  feet  in  height,  1  foot  8  inches  X  3  fget 
4  inches  square  at  the  bottom,  and  2X3  feet  10  inches  at  the  top.  The  intro 
duction  of  sloping  sides  has  been  found  advantageous.  Three  water  tuyeres  are 
placed  in  the  back  wall,  the  piers  between  which  the  furnaces  stand,  preventing 
t<  eir  introduction  at  the  sides. 

The  charge  consists  of  100  roasted  matte  and  about  93  slag,  partly  siliceous 
elag  from  the  ore  fusion,  and  partly  matte  slag  lepassed. 

The  products  are  (1)  Lead  containing  0'19  per  cent,  silver  and  more  copper, 
iron,  zinc,  antimony,  etc.,  than  the  metal  from  the  ore  ;  (2)  Copper  matte,  the 
composition  of  which  is  about : 

Sulphur 21-6    per  cent. 

Iron 392          •• 

Copper 23-7         " 

L  ad 15-0          " 

Silver 0-057     " 

(3)  Sbg  containing  2  per  cent,  lead,  and  0-002  per  cent,  silver.  When  copper  slag 
•was  used  as  a  precipitating  material,  the  mattes  from  this  fusion  contained  only 
11  per  cent,  of  copper,  a;>d  required  another  roasting  and  fusion  before  entering 
the  copper  process.  Now  this  is  unnecessary. 

The  treatment  of  the  copper  matte  consists  in  enriching  it  by  repeated  roast 
ing  and  fusion  with  siliceous  material,  to  black  copper  containing  95  per  cent, 
of  that  metal.  This  is  granulated,  treated  with  hot  sulphuric  acid,  the  c  pper 
sulphate  crystallized  out,  and  the  rich  residues  smelted  to' obtain  their  silver  and 
gold. 

The  copper  matte  is  roasted  in  the  kilns  described  above.  Fusions  take  place 
in  what  are  called  in  Germany  "spectacle"  furnaces.  They  are  10  ft.  8  in.  high, 
have  a  section  of  from  18  to  36  in.  X  3  ft.  4  in.,  and  owe  their  name  to  the  fact 
that,  they  have  two  reception  basins  in  front  They  have  one  tuyere  each,  use 


ALTEXAU. 


95 


250  cubic  foet  of  air  pT  minute  at  a  pressure  of  7  to  9  lines  of  mercury,  and 
smelt  from  9,300  to  10,000  Ib.  of  roasted  matte  in  21  hours.  The  composition 
of  the  charge  is  the  same  as  in  smelting  lead  matte,  except  that  instead  of  ore 
slag  a  siliceous  slag  from  another  operation  in  the  copper  process  is  charged.  A 
very  basic  slag  is  produced  which  eats  away  the  furnace  wall  so  rapidly  th\t  the 
campaigns  do  not  exceed  24  to  30  days.  The  roasting  and  fusion  is  repeated  five 
times,  and  KUHLEMANN  gives  the  following  summary  of  the  charges  and  products: 


FUSION   NUMBEB 

1 

2 

3 

4 

5 

Charge  :  K»asted  copper  matte  cwt. 
Siliceous  slag     ....                " 

50  ,f> 
3787 
988 
1375 
85(,)0 
10 
8G2 
27 
40 
20 
24)0 
6100 
0-79 
0-40 
47-30 

40 
55 
0-235 
40 
9 
0-0725 
1- 
0-75 
0  00093 

24  0 
1801 
480 
715 
30i,0 

Wio 
788 
210 
3  Go 
1400 

3)J 
225 
6<) 
95 
750 
10 
66} 
29-4 

125 
125 
290 

41-66 
41-06 

94 
2 
0-100 
73 
2 
0-045 
1-5 
1-25 
0-00063 

125 

95 
35 
30 
25J 

83i 

44 
6J 
14J 

35-20 
480 

05 
2 
0-083 
73 

0030 
1-25 

i 
0-00063 

Slag  from  same  operation..    " 
Fuel  :  Coke  ....                              " 

Pe<it         )  for  warming..  .  .pieces 
Charcoal  f      furnace              cu  ft 

Matte  melted  in  24  hours        cwt. 

SH 
29-8 

408 

1050 
2600 

17-0 
43  75 

70 
25 
0-22 
66 
5 
0-078 
1- 
1-5 
0-00125 

100 
34-7 

384 
300 
1160 

Coke  used  per  100  cwt.  matte 

1'roJucts:  Work  lead=0-38p.c.  silv.. 

Mutte  

K1:H»             

100  cwt  matte  give  Work  lead 

1  Slack  copper.  .  . 
Matte  

30-57 
28-57 

935 
1 
0-160 
70 
3 
0-065 
1 
0-75 
0-00063 

Cn1»rroSTTTON   OF   THK   PRODUCTS. 

Flack  copper  :  Copper     per  ct 

Lt-  n  d 

Matto:               Copper  

Lead     

Silver     

Sla"  l                 Copper                ... 

IjP'-lil                                          . 

Silver  

The  cLarge  in  each  lusion  was  therefore 

Roasted  matte 100     • 

Siliceous  slag 75 

Slag  trom  same  operation 20 

and  the  time  required  for  its  fusion  was  about  28  hours.  To  pass  100  cwt  of  tho 
first  matte  through  the  5  fusions  in  succession  requires  about  51  cwt  coke,  49 
hours  actual  smelting  time,  and  in  the  5  fusions  179  cwt.  matte  will  be  treated. 
The  data  above  given  are,  however,  only  a  portion  of  the  expenses.  Counting 
them  as  100  we  have  to  add  as  follows  : 

Expenses  in  fusion,  for  labor,  100 

"  roasting,  "  45 

"  removing  slag,  13| 

**  trauspor  ing  matte  '* 

"  general  expenses 97 

Tlie  entire  cost  will  be  about  165  p^r  cent,  of  the  cost  of  labor  and  fuel  con 
sumed  in  the  fu  duns. 


for  fuel,  100 
"         28 


06  ALTENAU. 

Tho  das  used  as  siliceous  flux  had  the  following  composition  : 

Silica 34-07        Lead  oxide 1  -07 

Alumina 4-D8        Iron  oxide 48-25 

Lime 3  53        Sulphur 1-25 

Manganese  oxide .  2  -00 

Zinc  oxide 2-89  98-64 

The  following  analysis  of  the  slag  from  the  5th  fusion  is  a  fair  representation  of 
the  same  product  from  all  the  operations  : 

Silica 30-994        Lime 4-314 

Antimony  oxide Of196        Magnesia 0-253 

Iron  oxide 58-605        Alumina 5-732 

Copper  oxide 0-933  

Lead  oxide 0-021  101  -048 

The  preceding  tables  show  that  a  certain  amount  oi  black  copper  is  mnde  in 
each  fusion.  That  from  the  first  operation  is,  however,  small  in  quantity  and 
qui^e  impure,  containing  a  good  deal  of  lead  and  silver.  The  total  amount  oF 
black  copper  from  all  the  operations  is  19  £  per  cent,  of  the  first  matte.  rJ  he 
greater  part  of  it  is  obtained  in  the  2d  and  3d  fusions. 

The  black  copper  from  all  the  fusions  is  mixed  with  purchased  copper  contain 
ing  silver,  and  "blown"  in  a  reverberatory  furnace.  The  mixture  contains  from 
0  16  to  0-20  per  cent,  silver  and  80  to  83  per  cent,  copper.  The  furnace  is  a 
cupel  hearth  of  the  old  form.  That  is  to  say,  the  roof  is  fixed  and  must  therefore 
be  high  enough  to  permit  the  workman  to  enter  the  furnace  to  make  the  hoarth. 
This  is  formed  of  claj"  and  coke  screenings,  with  a  border  of  mergel,  and  is  near 
ly  10  feet  in  diameter.  In  front  of  the  furnaca  is  a  water  basin  in  which  the  cop 
per  is  granulated  as  it  comes  out.  From  50  to  53  cwt.  of  black  copper  is  charg 
ed,  melted  in  5  hours,  a  "  carcase"  or  alloy  of  higher  fusing  point  than  the  black 
copper  is  drawn  off  from  the  surface,  and  air  is  blown  upon  the  bath,  at  first  in  a 
feeble  current  but  at  length  at  the  rate  of  250  cubic  feet  a  minute.  Lead,  iron, 
zinc,  cobalt,  nickel,  antimony  and  some  copper  are  oxidized  and,  drawing  silica 
from  the  hearth,  form  a  slag  which  is  drawn  or  run  off  from  the  surface.  After 
blowing  10  or  11  hours  the  refined  copper  is  tapped  and  granulated.  It  contains 
91  to  97  per  cent,  copper  and  0-20  to  0-40  per  cent,  silver.  The  analysis  of  a 
black  copper  made  in  this  way  in  1870  was  as  follows  : 

Iron 0-070        Copper 95-00 

Lead 2-71          Antimony 1-53 

Nickel,  cobalt,  zinc . .  0  -048        Arsenic traco 

Silver 0-30  

99-658 

In  the  Notes  on  Freiberg,  the  necessity  of  excluding  iron  from  the  matte 
•which  was  to  be  treated  with  acid,  and  the  means  used  to  accomplish  this,  were 
spoken  of.  It  will  be  observed  that  the  same  result  is  reached  at  Alteuau  by  re 
peated  roastings  and  fusions,  and  finally,  by  an  oxidizing  fusion  of  the  resulting 
black  copper. 

In  addition  to  the  black  copper,  two  products  are  obtained.  One  is  the  car 
case  drawn  off  from  the  bath  immediately  after  fusion.  It  contains  15  to  20  per 
cent,  silica,  5  per  cent,  nickel  oxide.  3£  per  cent,  cobalt  oxide,  10  to  12  per  cent, 
copper  oxide,  and  35  to  40  per  cent  lead  oxide.  The  amount  produced  is  small, 


ALTENAU.  97 

but  when  enough  has  accumulated,  it  will  be  smelted  with  arsenical  ores  and 
heavy  spar  to  produce  a  speise  rich  in  nickel.  The  other  product  is  the  very 
impure  litharge  obtained  by  blowing  the  black  copper,  and  containing  5  U  per 
cent  lead,  16  per  cent  copper,  and  0-016  per  cent  silver.  It  is  mixed  with  the 
hearth,  which  is  saturated  with  the  same  product,  and  smelted  to  a  black  copper 
containing  a  great  deal  of  lead  and  some  silver.  This  is  liquated  to  remove  tho 
lead,  and  then  blown  like  the  ordinary  black  copper,  furnishing,  however,  a 
much  greater  proportion  ot  side  products. 

The  following  are  the  details  of  the  operations  in  1869  : 

Number  of  charges »         74 

Black  copper  cwt        3,225|      100 

Products,  Granulated  copper "          2,201          68i 

Carcase "  63  2 

Litharge «  976          304 

Faggots * .  39,450      1220 

or  Bituminous  coal cwt.  42 

The  faggots  mentioned  are  now  replaced  by  bituminous  coal,  and  experience 
shows  that  1,000  faggots  are  equal  to  about  34i  cwt  coaL 

The  granulated  copper  is  treated  with  dilute  sulphuric  acid,  by  which  the  cop 
per,  iron,  nickel,  and  cobalt  are  dissolved,  leaving  a  residue  composed  of  gold, 
silver  and  arsenic  in  the  metallic  state,  lead  sulphate  and  basic  antimony  sul 
phate.  The  vats  in  which  the  solution  is  accomplished,  are  4  feet  high  and 
3  feet  4  inches  in  diameter.  They  are  lined  with  lead,  and  have  a  perforated 
f.xlse  bottom  4  inches  above  the  floor  of  the  vat.  Great  care  is  taken  in  filling 
the  vat,  for  it  is  important  to  have  the  mass  of  granules  as  open  and  porous  as 
possible.  While  copper  oxide  dissolves  readily  in  dilute  sulphuric  acid,  the 
m.tal  itself  requires  hot  concentrated  acid  for  its  solution.  At  Altenau  the 
metal  is  oxidized  by  allowing  the  acid  in  the  vat  to  run  out,  the  air  filling 
the  spaces  between  the  granules,  which,  being  hot  and  moist  with  arid,  oxidize, 
and  the  oxide  is  taken  up  by  the  succeeding  charge  of  acid.  To  ensure  the  com 
plete  access  of  air,  the  layer  of  copper  must  not  be  more  than  40  inches  thick,  so 
that  the  vat  holds  about  2,200  Ib.  It  is  filled  up  as  often  as  the  surface  fulls  10 
inches  below  the  normal  level,  which  occurs  two  or  three  times  a  week.  The 
vat  is  cleaned  out  once  in  eight  or  ten  weeks.  One  vat  suffices  to  dissolve  about 
93  IK  of  copper  per  day,  yielding  about  360  Ib.  of  vitriol 

The  sulphuric  acid  is  taken  direct  from  the  chambers,  and  marks  48  to  50  deg. 
B.  It  is  thinned  to  32  deg.  B.  in  a  tank  heated  by  steam  to  175  deg.  F.  Tue  diluted 
aci'l  is  throwu  on  the  copper,  by  means  of  a  lead  pipe  furnished  with  a  rose, 
every  half  hour.  The  acid  runs  through  rapidly,  but  has  time  to  dissolve  the 
oxid-.s  formed,  and  the  force  of  its  flow  is  sufficient  to  carry  along  the  fine  in 
soluble  residues.  This  is  an  important  point,  for  without  this  removal  of  the 
residues  not  only  will  the  granules  be  covered  with  an  insoluble  coat,  but  the 
interstices  will  also  be  filled  up.  A  turbid  liquor  discharging  from  the  spout  in 
the  bottom  of  the  vat  is  therefore  the  sign  of  a  good  operation.  This  spout 
being  left  open,  air  draws  through  the  mass  as  soon  as  the  interstices  are  free 
from  acid,  the  draft  being  aided  by  the  heat  of  the  copper,  derived  from  the  aciJ. 


03  ALTENAU. 

A  high  temperature  hastens  the  operation,  but  is  liable  to  cause  solution  of  the 
silver.  The  six  vats  at  Altenau  discharge  into  a  trough  360  feet  long,  where  the 
warm  solution  deposits  first  the  insoluble  residue  it  has  brought  along,  and  then, 
as  it  cools,  the  copper  sxilphate  crystallizes  out  The  trough  is  30  inches  wide 
and  7  inches  deep.  The  mother  liquor,  which  is  still  very  acid,  is  raised  to  the 
diluting  tank  by  means  of  a  Gifford's  injector,  made  of  lead. 

The  succeeding  operations  are  for  the  purification  of  the  copper  vitriol  and 
the  reduction  of  the  residue.  To  accomplish  the  former,  the  raw  vitriol  is  dis 
solved  in  hot  mother  liquor,  the  solution  marking  28  deg.  B.  It  is  filtered 
through  granulated  lead,  and  then  through  granulated  copper  to  remove  by 
precipitation  any  dissolved  silver,  and  also  to  retain  residues  that  were  too  fine 
to  settle  in  the  trough.  In  li  mouths  the  lead  and  copper  have  taken  up  1  per 
cent  of  silver,  and  are  removed.  The  copper  vitriol  is  crystallized  in  vats  lined 
with  lead,  and  with  strips  of  the  same  metal  hanging  in  the  liquor.  The  vats 
are  emptied  every  eleven  days,  and  the  crystals  dried.  Their  composition  is  : 

Iron 0  0107  per  cent. 

Antimony 0-0123         " 

Arsenic 0-0064        " 

Zinc trace 

Nickel 0  0  -06        •• 

Silver t;  ace 

Tot  1  impurty 0-0300  per  cent. 

Nine  dissolving  vats  nnd  three  re-dissolving  pans  treat  2,500  cwt.  of  copper 
yearly,  producing  about  9,000  cwt  of  vitriol.  Nine  men  are  employed  in  24 
Lours,  five  by  day  and  four  by  night 

The  argentiferous  residues  are  thrown  into  a  tank,  washed,  dried,  and  made 
up  into  balls  with  an  equal  quantity  of  litharge.  An  analysis  shows  that  they 
Contain  : 

Silver 3.10  Antimony 14.33 

Gold 0.004  Arsenic 3.15 

Copper 7.15  Sulphuric  Acid 16.67 

Lead 34.46 

The  copper  is  partly  sulphate  and  partly  fine  particles  which  are  washed  down 
by  the  acid.  The  subsequent  treatment  consists  in  smelting  the  mixed  litharge 
and  residue  in  a  shaft  furnace  and  cupelling  the  metal.  Care  is  taken  to  treat 
all  the  products  by  themselves,  as  they  are  very  rich  in  silver.  The  details  of 
the  foregoing  operations  are  ,,, ..  ... 

I.— VITBIOL  MANUTA.CTURE. 
Granulated  copper  treated cwt.  2305  100 


Copper  vitriol  produced 
Raw  vitriol. 


Argentiferous  residues  (one-half  litharge) . . 
Sulphuric  acid  consumed,  50-60  deg.  B . . . . 

Coal 

In  twenty- four  hours  copper  treated. 


8239  357* 

392  17 

342 

4373 
8336 
6-4 


1891 


vitriol  made •'         2  i  -88 


ALTENAU.  99 

IL— SMELTING  THE  RESIDUES. 
Charge  :  Residues cwt  342  100 


Litharge  and  hearth 

Iron 

Siliceous  slag 

Basic  slag 


Products  :Rich  work  lead 

Rich  copper  matte . 


674J  197J 

7  2 

608  1484 

372  108| 

481  1401      f 

49  Hi      , 

1347  394 

29!)  84| 


Coke  . 
Thirty  cwt  residues  were  smelted  in  24  hours. 

IIL  —  CUPELLATION. 

Charge  :    Work  lead cwt.  536  100 

Products:  Auriferous  silver Ib.    424  linei 

Ordinary  silver "      150 

Abstrich cwt.  114  214 

Litharge "     339  634 

Hearth "     148  27| 

Fuel:        Faggots 2862  495 

It  will  be  observed  that  while  100  parts  pure  copper  should  yield  393-37  parts 
vitriol,  the  product  from  the  impure  copper  used  was  357 '29  parts  of  merchanta 
ble  vitriol,  and  17  parts  retained  by  the  intermediate  products,  a  total  of  374-29, 
or  about  95  per  cent.  Nor  does  the  use  of  sulphuric  acid  correspond  with  the 
theoretical  requirements,  being  189-65  nstead  of  154-57,  as  required.  The  dif 
ference  is  due  to  the  fact  that  the  acid  used  is  really  below  66  deg.,  and  that  the 
intermediate  solutions  hold  a  considerable  amount  of  acid,  not  accounted  for. 

Labor  averages  54  cents  a  day,  and  the  coal,  which  is  of  good  quality  and  bears 
a  high  charge  for  transportation,  costs  about  $4.80  per  ton  (2240  Ib.),  and  cokai 
$6.  Under  these  conditions,  the  items  in  the  manufacture  of  vitriol  bore  the 
following  proportions: 

TBEATMENT  OF 
VITRIOL  MANUFACTUBE.  EESIDUE8. 

Sundries 8                                    7 

Labor 20                                 32| 

Acid 52 

Coal 20 

Coke 34J 

\vood 17 

General  Expenses  9 

100  100 

The  cost  of  treating  100  cwt.  of  40  per  cent  copper  matte  was,  in  1869,  301 
thalers  7i  sgr.,  or  (thaler=72  cents  gold)  $216.90.  While  this  is  apparently 
high,  it  is  to  be  remembered  that  much  of  it  is  due  to  the  acid  employed,  which, 
however,  does  not  go  to  waste,  but  is  sold  as  a  part  of  the  finished  product 
Compared  with  the  old  liquation  process,  the  present  system  extracts  about  eight 
per  cent,  more  silver,  and  is  in  every  respect  superior. 

The  results  of  the  treatment  described  above  are  very  remarkable  in  respect  to 
the  percentage  of  the  different  metals  obtained  from  the  ore.     KOCH  gave  the 
production  by  the  "  combined"  process  or  fusion  of  roasted  matte  with  the  ore  as, 
Silver,  102-5  per  cent,  of  assayed  value  of  ore. 
Lead,  100-8        " 
Copper,  100-3    «•  •«  " 


100  ALTENAIT. 

Thus  the  smelting  operations  gave  more  metal  than  the  assay  calls  for,  a  cir 
cumstance  that  is,  of  course,  due  to  the  fact  that  losses  take  place  in  making  the 
assay  which  are  not  accounted  for.  WEDDING  &  BRJBONNING  found  that  by  the 
desilverization  process  now  in  use  the  amount  of  silver  extracted  is  2-372  per 
cent,  more  than  the  assay  shows  to  be  present  in  the  lead.  If,  however,  the  sil 
ver  absorbed  by  the  cupel  is  allowed  for  at  3  per  cent. ,  there  would  be  a  real  loss 
of  0-628  per  cent,  of  silver.  Similar  corrections  would  make  still  larger  differences 
between  the  apparent  and  the  real  extraction  of  the  other  metals.  But  the  Hartz 
process  is,  nevertheless,  remarkable  for  the  closeness  with  which  it  works  to  the 
assay.  The  exact  loss  is  not  known,  but  it  is  less  than  4  per  cent,  of  lead,  and 
probably  less  than  1  per  cent,  silver.  These  results  are  especially  significant 
from  the  fact  that  the  Hartz  works  treat  unroasted  ore,  and  they  sustain  the  view 
of  PLATTNER,  who  looked  upon  the  process  of  roasting  as  one  decidedly  wasteful 
of  metal,  by  volatilization.  Another  cause  of  the  small  loss  is  the  persistence 
with  which  intermediate  products  of  only  moderate  richness  are  reduced  to  metal 
and  again  desilvered,  a  method  which  would  not  always  pay  in  America. 

But  the  close  extraction  of  metal  is  not  the  only  proof  of  good  work  in  the 
Hartz.  The  directors  of  the  various  smelting  works  there  are  the  first  to  solve 
the  problem  of  utilizing  the  sulphur  in  galena  for  the  manufacture  of  acid. 
Pure  galena  contains  only  about  13  per  cent,  of  sulphur,  a  quantity  too  small  to 
be  utilized  with  profit.  It  is  only  by  concentrating  this  element  in  a  matte  that 
it  can  be  made  to  give  sufficiently  concentrated  fumes  for  oxidation  in  the  lead 
chambers.  But  this  matte  usually  contains  so  much  lead  that  it  sinters  at  a  low 
heat,  a  difficulty  that  has  heretofore  barred  the  way  to  its  use  in  kilns,  as  a  source 
of  acid.  The  introduction  of  the  precipitation  by  slag  taught  the  Clausthal 
metallurgists  that  it  is  possible  to  make  a  matte  poor  in  lead  from  lead  ores.  It 
seems  to  be  probable  that  precipitation  is  more  thoroughly  performed  when  the 
ore  trickles  through  a  bath  of  slag  rich  in  iron  than  when  it  is  brought  in  contact 
with  metallic  iron,  even  when  the  heat  is  sufficient  to  melt  the  latter.  The  intro 
duction  of  precipitation  by  slag  increased  the  amount  of  matte  produced,  but  it 
decreased  its  percentage  of  lead  from  40  to  7  or  10  per  cent.,  and  the  latter  limits 
have  been  retained  in  the  matte  from  the  combined  fusion  of  ore  and  matte.  In 
addition  to  the  metals  they  contain,  the  Hartz  ores,  which  are  true  galenas,  are 
now  made  to  yield  a  part  of  their  sulphur  as  acid. 

I  have  found  it  impossible  to  obtain  any  trustworthy  calculations  of  the  cost  of 
the  above  treatment.  The  following  is  probably  not  very  far  from  the  truth,  ra 
ther  under  than  over.  The  calculation  is  made  on  one  European  ton,  1000  k= 

2200  Ib. : 

Ore  and  lead  matte  fusions,  2200  Ib.  ore $7. 82 

Treatment  of  copper  matte,  1 10  Ib 2. 60 

Treatment  of  lead  matte,  1227  Ib 2.76 

$13.18  (coin) 

The  products  are  about  as  follows,  allowing  the  production  of  copper  to  form 
1  per  cent,  of  the  ore: 

Lead 1210  Ib.,  or  a  loss  of  about  1£  per  cent. 

Sulphate  of  copper,  781  Ib. 

Silver 2  Ib. ;  loss  supposed  to  be  about  |  oz. 

Skilled  labor  costs  in  the  Hartz  from  48  to  54  cents  coin,  and  ordinary  labor, 


ALTENAU. 

say  from  36  to  43  cents.  Coke  costs  $6.70  per  ton;  soft  coal,  $4.80;  a  "Bollock," 
or  60  faggots  of  wood  (equal  to  225  Ib.  soft  coal  in  use),  96  cents;  and  the  cop 
per  slag  used  as  a  flux  in  the  ore  fusion  is  brought  from  Oker  at  a  cost  of  96  cents 
a  ton. 

THE  OPERATIONS  IN  1871. 

Doctor  WEDDING  contributes  every  year  to  the  Preussische  Zeitschrifl  fiir 
Berg,  Hiitten  und  Saiinen  Westn,  which  is  the  official  mining  journal  of  the 
Prussian  Government,  an  account  of  the  current  experiments  and  improvements 
in  the  smeltiug  works  of  that  Government  His  report  of  the  progress  made 
during  1871  gives  so  much  relating  to  the  Hartz,  that  I  take  from  it  the  follow 
ing  details: 

The  mines  of  the  Upper  Hartz  yielded  in  1871:  154,622  tons  (2204  Ib.)  of  ore, 
which  by  concentration  was  reduced  to  13,546  tons  of  smelting  ore,  having  a 
composition  similar  to  that  given  above.  The  smelting  ore,  therefore,  formed 
8-7  per  cent  of  the  mine  ore,  and  the  latter,  as  it  was  hoisted  from  the  mine, 
must  have  averaged  about  as  follows:  Lead,  £  '4  per  cent ;  Copper,  0-065  per  cent. ; 
Silver,  0-0085  per  cent,  or  3i  oz.  to  the  ton.  During  that  year  the  smelting 
works  treated  13,911  tons  of  home  and  497  tons  of  foreign  ore,  and  produced 
7,930  tons  lead,  47  i  tons  litharge,  41-58  Ib.  gold,  and  37,523  Ib.  silver.  Of  this 
ore,  9,150  tons  were  smelted  at  Clausthal,  seven  furnaces  being  used  for  the  first 
fusion.  Five  of  them  were  round  furnaces,  of  the  EAST  and  PILTZ  pattern,  three 
having  4  tuyeres,  one  5,  and  one  8  tuyeres.  Two  KACHETTE  furnaces,  each  with 
12  tuyeres,  were  also  in  operation. 

The  charge  consisted  of  100     ore, 

•«  "  51     roasted  matte, 

•«  •«  67     copper  slag, 

"  «•  43     matte  slag, 

•«  ••  47    slag  from  the  same  operation, 

308 

1  -2  scraps, 
1  -0  flue  dust, 
0-5  lead  scraps. 
27 

310-7 

The  fuel,  including  the  small  coke  used  in  making  the  "gestttbbe,"  which  forms 
the  fore  hearth,  and  also  that  used  to  warm  the  furnaces,  amounted  to 

45-17  coke, 
2-55  charcoal, 

47-72 

or  15i  per  cent,  of  the  total  charge,  and  47|  per  cent,  of  the  ore. 

The  products  were: 

58-77  wo  k  lead, 
76 -U9  matte. 
124-86 

If  the  amount  of  matte  charged  is  deducted  from  that  produced,  only  25  per 
cent,  remains,  which  is  a  very  much  smaller  proportion  than  that  obtained  in 
any  former  modification  of  the  Clausthal  process. '  In  working  the  8-tuyered  fur 
nace,  which  at  first  had  a  crucible  of  4  ft  8  in.  diameter,  it  was  found  impossible 
to  blow  to  the  center  of  the  charge,  where  a  pillar  of  unsmelted  material  always 


102 


ALTENAU. 


remained.  By  shoving  the  tuyeres  toward  the  center  until  the  diameter  of  th« 
working  hearth  was  reduced  to  1  meter,  or  3  ft.  4.  in.,  this  difficulty  was  removed, 
and  this  has,  therefore,  been  fixed  upon  as  the  standard  of  a  new  Piltz,  which 
will  have  but  4  tuyeres.  The  other  round  furnaces  do  very  good  work,  running 
through  20  tons  of  charge  (6-7  to  is  ore)  in  24  hours. 

At  Altenau,  202-6  tons  of  black  copper  were  treated,  producing  288,700  Ib. 
copper,  822 -56  Ib.  silver,  and  4,275  tons  of  sulphuric  acid. 

From  the  four  establishments  at  Clausthal,  Lautenthal,  Alteuau  and  Andrea* 
berg,  there  were  produced  in  1871  the  following  amounts: 

43-63  Ib.  gold, 
37,523-0    IK  silver, 
7,929-4    tons  lead, 
47-5      "    litharge, 
602-0      "    refined  copper, 
6,132-0      "    copper  vitriol, 
427 '5      "    sulphuric  acid, 

22-5      ••    lead  paint, 
This  had  a  value  of  $1,497,965. 


SCIENTIFIC  BOOKS 

PUBLISHED  BY 

D.  VAN  NOSTBAND, 

23  MURRAY  STREET  &  27  WARREN  STREET, 
NEW    YORK. 


Weisbacli's  Mechanics. 

New  and  Revised  Edition* 

8vo.     Cloth.     $10.00. 

A  MANUAL  OF  THE  MECHANICS  OF  ENGINEERING, 
and  of  the  Construction  of  Machines.  By  JULIUS  WEISBACH,  PH. 
D.  Translated  from  the  fourth  augmented  and  improved  Ger 
man  edition,  by  ECKLEY  B.  COXE,  A.M.,  Mining  Engineer.  Vol. 
I. — Theoretical  Mechanics.  1,100  pages,  and  902  wood-cut 
illustrations. 

ABSTRACT  OP  CONTENTS. — Introduction  to  the  Calculus — The  General 
Principles  of  Mechanics — Phoronomics,  or  the  Purely  Mathematical  Theory 
of  Motion — Mechanics,  or  the  General  Physical  Theory  of  Motion  Statics  of 
Rigid  Bodies — The  Application  of  Statics  to  Elasticity  and  Strength — Dynam 
ics  of  Rigid  Bodies -Statics  of  Fluids  -  Dynamics  of  Fluids— The  Theory 
of  Oscillation,  etc. 

"  The  present  edition  is  an  entirely  new  work,  greatly  extended  and  very 
much  improved.  It  forms  a  text-book  which  must  find  its  way  into  the  hands, 
not  only  of  every  student,  but  of  every  engineer  who  desires  to  refresh  his  mem 
ory  or  acquire  clear  ideas  on  doubtful  points.'' — Manufacturer  and  Builder. 

"  We  hope  the  day  is  not  far  distant  when  a  thorough  course  of  study  and 
education  as  such  shall  be  demanded  of  the  practising  engineer,  and  with  this 
view  we  are  glad  to  welcome  this  translation  to  our  tongue  and  shores  of  one 
of  the  most  able  of  the  educators  of  Europe." — Tlie  Technologist. 


1  SCIENTIFIC  BOOKS  PUBLISHED  BY 

Francis'  Lowell  Hydraulics. 

Third  Edition. 

4to.     Cloth.     $15.00. 

LOWELL  HYDRAULIC  EXPERIMENTS  —  being-  a  Selec 
tion  from  Experiments  on  Hydraulic  Motors,  on  the  Flow  of 
Water  over  Weirs,  and  in  Open  Canals  of  Uniform  Rectangular 
Section,  made  at  Lowell,  Mass.  By  J.  B.  ERANCIS,  Civil  Engineer. 
Third  edition,  revised  and  enlarged,  including  many  New  Ex 
periments  on  Gauging  Water  in  Open  Canals,  and  on  the  Elow 
through  Submerged  Orifices  and  Diverging  Tubes.  With  23 
copperplates,  beautifully  engraved,  and  about  100  new  pages  of 
text. 

The  work  is  divided  into  parts.  PART  I.,  on  hydraulic  motors,  includes 
ninety-two  experiments  on  an  improved  Fourneyron  Turbine  "Water-Wheel, 
of  about  two  hundred  horse-power,  with  rules  and  tables  for  the  construction 
of  similar  motors;  thirteen  experiments  on  a  model  of  a  centre- vent  water- 
wheel  of  the  most  simple  design,  and  thirty-nine  experiments  on  a  centre-vent 
water- wheel  of  about  two  hundred  and  thirty  horse-power. 

PART  II.  includes  serenty-four  experiments  made  for  the  purpose  of  deter 
mining  the  form  of  the  formula  for  computing  the  flow  of  water  over  weirs ; 
nine  experiments  on  the  effect  of  back-water  on  the  flow  over  weirs;  eighty- 
eight  experiments  made  for  the  purpose  of  determining  the  formula  for  com 
puting  the  flow  over  weirs  of  regular  or  standard  forms,  with  several  table* 
of  comparisons  of  the  new  formula  with  the  results  obtained  by  former  experi 
menters;  five  experiments  on  the  flow  over  a  dam  in  which  the  crest  was  of  the 
same  form  as  that  built  by  the  Essex  Company  across  the  Merrimack  River  at 
Lawrence,  Massachusetts;  twenty -one  experiments  on  the  effect  of  observing 
the  depths  of  water  on  a  weir  at  different  distances  from  the  weir ;  an  exten 
sive  series  of  experiments  made  for  the  purpose  of  determining  rules  for 
gauging  streams  of  water  in  open  canals,  with  tables  for  facilitating  the  same ; 
and  one  hundred  and  one  experiments  on  the  discharge  of  water  through  sub- 
Merged  orifices  and  diverging  tubes,  the  whole  being  fully  illustrated  by 
twenty-three  double  plates  engraved  on  copper. 

In  1855  the  proprietors  of  the  Locks  and  Canals  on  Merrimack  River  con 
sented  to  the  publication  of  the  first  edition  of  this  work,  which  contained  a 
selection  of  the  most  important  hydraulic  experiments  made  at  Lowell  up  to 
that  time.  In  this  edition  the  principal  hydraulic  experiments  made  there, 
subsequent  to  1855,  have  be^n  added,  including  the  important  series  above 
mentioned,  for  determining  rules  for  the  gauging  the  flow  of  water  in  open 
canals,  and  the  interesting  series  on  the  flow  through  a  submerged  Venturi's 
tube,  in  which  a  larger  flow  was  obtained  than  any  we  find  recorded. 


J).   VAN  NOSTIIAJSTD. 


Francis  on  Oast-Iron  Pillars. 

8vo.     Cloth.     $2.00. 

ON  THE  STRENGTH  OF  CAST-IRON  PILLARS,  with  Tables 
for  the  use  of  Engineers,  Architects,  and  Builders.  By  JAMES  B. 
FBANCIS,  Civil  Engineer. 


Merrill's  Iron  Truss  Bridges. 

Second  Edition. 

4to.     Cloth.     $5.00. 

IRON  TRUSS  BRIDGES  FOR  RAILROADS.  The  Method  of 
Calculating  Strains  in  Trusses,  with  a  careful  comparison  of  the 
most  prominent  Trusses,  in  reference  to  economy  in  combination, 
etc.,  etc.  By  Brevet  Colonel  WILLIAM  E.  MERRILL,  U.S.A., 
Major  Corps  of  Engineers.  Nine  lithographed  plates  of  illustra 
tions. 

"  The  work  before  us  is  an  attempt  to  give  a  basis  for  sound  reform  in  this 
feature  of  railroad  engineering,  by  throwing  '  additional  light  upon  the 
method  of  calculating  the  maxima  strains  that  can  come  upon  any  part  of  a 
bridge  truss,  and  upon  the  manner  of  proportioning  each  part,  so  that  it  shall 
be  as  strong  relatively  to  its  own  strains  as  any  other  part,  and  so  that  the 
entire  bridge  may  be  strong-  enough  to  sustain  several  times  as  great  strains 
as  the  greatest  that  can  come  upon  it  in  actual  use.'  " — Scientific  American. 

"  The  author  has  presented  his  views  in  a  clear  and  intelligent  manner,  and 
the  ingenuity  displayed  in  coloring  the  figures  so  as  to  present  certain  facts 
to  the  eye  forms  no  inappreciable  part  of  the  merits  of  the  work.  The  reduc 
tion  of  the  *  formulae  for  obtaining  the  strength,  volume,  and  weight  of  a  cast- 
iron  pillar  under  a  strain  of  compression,'  will  be  very  acceptable  to  those  who 
have  occasion  hereafter  to  make  investigations  involving  these  conditions.  As 
a  whole,  the  work  has  been  well  done." — Railroad  Gazette,  Chicago. 


Humber's  Strains  in  Girders. 

ISmo.     Cloth.     $2.50. 

A  HANDY  BOOK  FOR  THE  CALCULATION  OF  STRAINS 
IN  GIRDERS  and  Similar  Structures,  and  their  Strength,  con 
sisting  of  Formulae  and  Corresponding  Diagrams,  with  numerous 
details  for  practical  application.  By  WILLIAM  HDMBER.  Fully 
illustrated. 


SCIENTIFIC  BOOKS  PUBLISHED  BY 


Shreve  on  Bridges  and  Roofs. 

8ro,  87  wood-cut  illustrations.    Cloth.     $5.00. 

A   TREATISE    ON    THE   STRENGTH    OF   BRIDGES  AND 

ROOFS — comprising  the  determination  of  Algebraic  formulas 
for  Strains  in  Horizontal,  Inclined  or  Rafter,  Triangular,  Bow 
string,  Lenticular  and  other  Trusses,  from  fixed  and  moving 
loads,  with  practical  applications  and  examples,  for  the  use  of 
Students  and  Engineers.  By  SAMUEL  H.  SHREYE,  A.M.,  Civil 
Engineer. 

The  rules  for  the  determination  of  strains  given  in  this  work,  in  the  shape 
of  formulas,  are  deduced  from  a  few  well-known  mechanical  laws,  and  are  not 
based  upon  assumed  conditions;  the  processes  are  given  and  applications 
made  of  the  results,  so  that  it  is  equally  valuable  as  a  text-book  for  the 
Student  and  as  a  manual  for  the  Practical  Engineer.  Among  the  example^ 
are  the  G-reithausen  Bridge,  the  Kuilemberg  Bridge,  a  bridge  of  the  Saltash 
type,  and  many  other  compound  trusses,  whose  strains  are  calculated  by 
methods  which  are  not  only  free  from  the  use  of  the  higher  mathematics,  but 
are  as  simple  and  accurate,  and  as  readily  applied,  as  those  which  are  used  in 
proportioning  a  Warren  G-irder  or  other  simple  truss. 


The  Kansas  City  Bridge. 

4to.     Cloth.     $6.00 

WITH  AN  ACCOUNT  OF  THE  REGIMEN  OF  THE  MIS 
SOURI  RIVER,  and  a  description  of  the  Methods  used  for 
Founding  in  that  River.  By  0.  CHANUTE,  Chief  Engineer,  and 
GEORGE  MORISON,  Assistant  Engineer.  Illustrated  with  five 
lithographic  views  and  twelve  plates  of  plans. 

Illustrations. 


VIEWS. — View  of  the  Kansas  City 
Bridge,  August  2,  1869.  Lowering 
Caisson  No.  1  into  position.  Caisson 
for  Pier  No.  4  brought  into  position. 
View  of  Foundation  Works,  Pier  No. 


tion  Works,  Pier  No.  3.  IV.  Founda 
tion  Works,  Pier  No.  4.  V.  Founda 
tion  Works,  Pier  No.  4.  VI.  Caisson 
No.  5 — Sheet  Piling  at  Pier  No.  6— 
Details  of  Dredges — Pile  Shoe — Beton 


4.     Pier  No.  1.  j  Box.      VII.  Masonry — Draw  Protec- 

PLATES. — I.  Map  showing  location      tion — False  Works  between  Piers  3 


of  Bridge.  II.  Water  Record— Cross 
Section  of  River — Profile  of  Crossing 
— Pontoon  Protection.  III.  Water 


and    4.       VIII.     Floating    Derricks. 

IX.  General  Elevation — 1 76  feet  span. 

X.  248  feet  span.   XI.  Plans  of  Draw. 


Deadener — Caisson    No.    2 — Founda    j  XII.  Strain  Diagrams. 


D.  VAN  NOSTRAND. 


Clarke's    Quincy  Bridge. 

4to.    Cloth.     $7.50. 

DESCRIPTION  OF  THE  IRON  RAILWAY  Bridge  across  the 
Mississippi  River  at  Qiiincy,  Illinois.  By  THOMAS  CURTIS  CLARKE, 
Chief  Engineer.  Illustrated  with  twenty-one  lithographed 
plans. 

Illustrations. 


PLATES. — General  Plan  of  Missis 
sippi  River  at  Quincy,  showing  loca 
tion  of  Bridge.  II<z.  General  Sections 
of  Mississippi  River  at  Quincy,  show 
ing  location  of  Bridge.  116.  General 
Sections  of  Mississippi  River  at  Quin 
cy,  showing  location  of  Bridge.  III. 
General  Sections  of  Mississippi  River 
at  Quincy,  showing  location  of  Bridge. 
IV.  Plans  of  Masonry.  V.  Diagram 
of  Spans,  showing  the  Dimensions, 
Arrangement  of  Panels,  etc.  VI.  Two 
hundred  and  fifty  feet  span,  and  de 
tails.  VII.  Three  hundred  and  sixty 
feet  Pivot  Draw.  VIII.  Details  of 
three  hundred  and  sixty  feet  Draw. 
IX.  Ice- Breakers,  Foundations  of  Piers 
and  Abutments,  Water  Table,  and 


Curve  of  Deflections.  X.  Founda 
tions  of  Pier  2,  in  Process  of  Con 
struction.  XI.  Foundations  of  Pier 
3,  and  its  Protection.  XII.  Founda 
tions  of  Pier  3,  in  Process  of  Construc 
tion,  and  Steam  Dredge.  XIII.  Foun 
dations  of  Piers  5  to  18,  in  Process 
of  Construction.  XIV.  False  Works, 
showing  Process  of  Handling  and  Set 
ting  Stone.  XV.  False  Works  for 
Raising  Iron  Work  of  Superstructure. 
XVI.  Steam  Dredge  used  in  Founda 
tions  9  to  18.  XVII.  Single  Bucket 
Dredge  used  in  Foundations  of  Bay 
Piers.  XVIII.  Saws  used  for  Cut 
ting  Piles  under  water.  XIX.  Sand 
Pump  and  Concrete  Box.  XX  Ma 
sonry  Travelling  Crane. 


Whipple  on  Bridge  Building. 

8vo,  Illustrated.     Cloth.     $4.00. 

AN  ELEMENTARY  AND  PRACTICAL  TREATISE  ON 
BRIDGE  BUILDING.  An  enlarged  and  improved  edition  of 
the  Author's  original  work.  By  S.  WHIPPLE,  C.  E.,  Inventor  of 
the  Whipple  Bridges,  &c. 

The  design  has  been  to  develop  from  Fundamental  Principles  a  system  easy 
of  comprehension,  and  such  as  to  enable  the  attentive  reader  and  student  to 
judge  understandingly  for  himself,  as  to  the  relative  merits  of  different  plans 
and  combinations,  and  to  adopt  for  use  such  as  may  be  most  suitable  for  the 
cases  he  may  have  to  deal  with. 

It  is  hoped  the  work  may  prove  an  appropriate  Text-Book  upon  the  subject 
treated  of,  for  the  Engineering  Student,  and  a  useful  manual  for  the  Practic 
ing  Engineer  and  Bridge  Builder. 


6  SCIENTIFIC  BOOKS  PUBLISHED     BY 

Stoney  on  Strains. 

New  and  Revised  Edition,  with  numerous  illustrations. 

Royal  8vo,  664  pp.     Cloth.    $15.00. 

THE  THEORY  OF  STRAINS  IN  GIRDERS  and  Similar  Struc 
tures,  with  Observations  on  the  Application  of  Theory  to  Practice, 
and  Tables  of  Strength  and  other  Properties  of  Materials.  By 
BIND  ON  B.  STONEY,  B.  A. 


Roebling's  Bridges. 

Imperial  folio.     Cloth.     $25.00. 

LONG  AND  SHORT  SPAN  RAILWAY  BRIDGES.  By  JOHN 
A.  ROEBLING,  C.  E.  Illustrated  with  large  copperplate  engrav 
ings  of  plans  and  views.  , 

List  of  Plates 

1.  Parabolic  Truss  Bail  way  Bridge.  2,  3,  4,  5,  6.  Details  of  Parabolic 
Truss,  with  centre  span  500  feet  in  the  clear.  7.  Plan  and  View  of  a  Bridge 
over  the  Mississippi  River,  at  St.  Louis,  for  railway  and  common  travel.  8,  9, 
10,  11,  12.  Details  and  View  of  St.  Louis  Bridge.  13.  Railroad  Bridge  over 
the  Ohio. 

Diedrichs'  Theory  of  Strains. 

8vo.     Cloth.     $5.00. 

A  Compendium  for  the  Calculation  and  Construction  of  Bridges, 
Roofs,  and  Cranes,  with  the  Application  of  Trigonometrical 
Notes.  Containing  the  most  comprehensive  information  in  re 
gard  to  the  Resulting  Strains  for  a  permanent  Load,  as  also  for 
a  combined  (Permanent  and  Rolling)  Load.  In  two  sections 
adapted  to  the  requirements  of  the  present  time.  By  JOHN  DIED- 
EICHS.  Illustrated  by  numerous  plates  and  diagrams, 

"  The  want  of  a  compact,  universal  and  popular  treatise  on  the  Construe-' 
tion  of  Roofs  and  Bridges — especially  one  treating  of  the  influence  of  a  varia 
ble  load — and  the  unsatisfactory  essays  of  different  authors  on  the  subject, 
induced  me  to  prepare  fhis  work." 


D.   VAN  NOSTRAND. 


Whilden's  Strength  of  Materials, 

12mo.     Cloth.     $2.00. 

ON  THE  STEENGTH  OF  MATEEIALS  used  in  Engineering 
Construction.     By  J.  K.  WHILDEN. 


Oampin  on  Iron  Roofs. 

Large  8vo.     Cloth.     $3.00. 

ON  THE  CONSTEUCTION  OF  IEON  EOOFS.  A  Theoretical 
and  Practical  Treatise.  By  FEANCIS  CAMPIN.  With,  wood-cuts 
and  plates  of  Eoofs  lately  executed. 

"  The  mathematical  formulas  are  of  an  elementary  kind,  and  the  process 
admits  of  an  easy  extension  so  as  to  embrace  the  prominent  varieties  of  iron 
truss  bridges.  The  treatise,  though  of  a  practical  scientific  character,  may  be 
easily  mastered  by  any  one  familiar  with  elementary  mechanics  and  plane 
trigonometry." 

Holley's  Railway  Practice. 

1  vol.  folio.     Cloth.     $12.00. 

AMEEICAN  AND   EUEOPEAN  EAILWAY  PEACTICE,   in 

the  Economical  Generation  of  Steam,  including  the  materials 
and  construction  of  Coal-burning  Boilers,  Combustion,  the  Varia 
ble  Blast,  Vaporization,  Circulation,  Super-heating,  Supplying 
and  Heating  Feed- water,  &c.,  and  the  adaptation  of  Wood  and 
Coke-burning  Engines  to  Coal-burning  ;  and  in  Permanent  Way, 
including  Eoad-bed,  Sleepers,  Eails,  Joint  Fastenings,  Street 
Eailways,  &c.,  &c.  By  ALEXANDER  L.  HOLLET,  B.  P.  With  77 
lithographed  plates. 

"  This  is  an  elaborate  treatise  by  one  of  our  ablest  civil  engineers,  on  the  con 
struction  and  use  of  locomotives,  with  a  few  chapters  on  the  building  of  liail- 
roc.ds.  *  *  *  All  these  subjects  are  treated  by  the  author,  who  is  a 
first-class  railroad  engineer,  in  both  an  intelligent  and  intelligible  manner.  The 
f^cts  and  ideas  are  well  arranged,  and  presented  in  a  clear  and  simple  style, 
accompanied  by  beautiful  engravings,  and  we  presume  the  work  will  be jregard- 
ed  as  indispensable  by  all  who  are  interested  in  a  knowledge  of  the  construc 
tion  of  railroads  and  rolling  stock,  or  the  working  of  locomotives." — /Scientific 
American. 


8  SCIENTIFIC  BOOKS  PUBLISHED  BY 

Henrici's  Skeleton  Structures. 

8vo.    Cloth.    $3.00. 

SKELETON  STRUCTURES,  especially  in  their  Application  to 
the  building  of  Steel  and  Iron  Bridges.  By  OLAUS  HENRICI. 
With  folding  plates  and  diagrams. 

By  presenting  these  general  examinations  on  Skeleton  Structures,  •with 
particular  application  for  Suspended  Bridges,  to  Engineers,  I  renture  to  ex 
press  the  hope  that  they  will  receive  these  theoretical  results  with  some  confi 
dence,  even  although  an  opportunity  is  wanting  to  compare  them  with  practi 
cal  results.  O.  H. 


Useful  Information  for  Railway  Men. 

Pocket  form.     Morocco,  gilt,  $2.00. 

Compiled  by  W.  G.  HAMILTON,  Engineer.     Fifth    edition,  revised 
and  enlarged.     570  pages. 

"  It  embodies  many  valuable  formulae  and  recipes  useful  for  railway  men, 
and,  indeed,  for  almost  every  class  of  persons  in  the  world.  The  '  informa 
tion  '  comprises  some  valuable  formulae  and  rules  for  the  construction  of 
boilers  and  engines,  masonry,  properties  of  steel  and  iron,  and  the  strength 
of  materials  generally." — Railroad  Gazette,  Chicago. 


Brooklyn  Water  Works. 

1  vol.  folio.     Cloth.     $20.00. 

A  DESCEIPTIVE  ACCOUNT  OF  THE  CONSTKUCTION  OF 
THE  WORKS,  and  also  Reports  on  the  Brooklyn,  Hartford, 
Belleville,  and  Cambridge  Pumping  Engines.  Prepared  and 
printed  by  order  of  the  Board  of  Water  Commissioners.  With 
59  illustrations. 

CONTENTS. — Supply  Ponds — The  Conduit  —  Bidgewood  Engine  House  and 
Pump  Well — Ridge  wood  Engines — Force  Mains — Ridge  wood  Reservoir — 
Pipe  Distribution — Mount  Prospect  Reservoir — Mount  Prospect  Engine 
House  and  Engine — Drainage  Grounds — Sewerage  Works — Appendix. 


D.  VAJST  NOSTRAND. 


Kirkwood  on  Filtration. 

4to.     Cloth.     $15.00. 

REPORT  ON  THE  FILTKATION  OF  RIVER  WATERS,  for 

the  Supply  of  Cities,  as  practised  in  Europe,  made  to  the  Board 
of  Water  Commissioners  of  the  City  of  St.  Louis.  By  JAMES  P. 
KIRKWOOD.  Illustrated  by  30  double-plate  engravings. 

CONTENTS. — Report  on  Filtration — London  "Works,  General — Chelsea 
Water  Works  and  Filters— Lambeth  Water  Works  and  Filters— Southwark 
and  Vauxhall  Water  Works  and  Filters — Grand  Junction  Water  Works  and 
Filters— West  Middlesex  Water  Works  and  Filters— New  River  Water 
Works  and  Filters— East  London  Water  Works  and  Filters— Leicester  Water 
Works  and  Filters— York  Water  Works  and  Filters— Liverpool  Water  Works 
and  Filters— Edinburgh  Water  Works  and  Filters— Dublin  Water  Works 
and  Filters— Perth  Water  Works  and  Filtering  Gallery— Berlin  Water 
Works  and  Filters — Hamburg  Water  Works  and  Reservoirs — Altona  Water 
Works  and  Filters — Tours  Water  Works  and  Filtering  Canal — Angers  Water 
Works  and  Filtering  Galleries — Nantes  Water  Works  and  Filters — Lyons 
Water  Works  and  Filtering  Galleries— Toulouse  Water  Works  and  Filtering 
Galleries — Marseilles  Water  Works  and  Filters — Genoa  Water  Works  and 
Filtering  Galleries— Leghorn  Water  Works  and  Cisterns— Wakefield  Water 
Works  and  Filters — Appendix. 


Tanner  on  Roll-Turning. 

1  vol.  8vo.  and  1  vol.  plates.     $10.00. 

A  TREATISE  ON  ROLL-TURNING  FOR  THE  MANUFAC 
TURE  OF  IRON.  By  PETER  TUXNER.  Translated  and  adapted. 
By  JOHN  B.  PEA.BSE,  of  the  Pennsylvania  Steel  Works.  With 
numerous  wood-cuts,  8v6.,  together  with  a  folio  atlas  of  10  litho 
graphed  plates  of  Rolls,  Measurements,  &c. 

"  We  commend  this  book  as  a  clear,  elaborate,  and  practical  treatise  upon 
the  department  of  iron  manufacturing  operations  to  which  it  is  devoted. 
The  writer  states  in  his  preface,  that  for  twenty -five  years  he  has  felt  the 
necessity  of  such  a  work,  and  has  evidently  brought  to  its  preparation  the 
fruits  of  experience,  a  painstaking  regard  for  accuracy  of  statement,  and  a 
desire  to  furnish  information  in  a  style  readily  understood.  The  book  should 
be  in  the  hands  of  every  one  interested,  either  in  the  general  practice  of 
mechanical  engineering,  or  the  special  branch  of  manufacturing  operations  to 
which  the  work  relates.' — American  Artisan. 


10  SCIENTIFIC  BOOKS  PUBLISHED  BY 

G-lynn  on  the  Power  of  Water. 

12mo.     Cloth.     $1.00. 

A  TREATISE  ON  THE  POWER  OF  WATER,  as  applied  to 
drive  Flour  Mills,  and  to  give  motion  to  Turbines  and  other 
Hydrostatic  Engines.  By  JOSEPH:  GLYNN,  F.R.  S.  Third  edition, 
revised  and  enlarged,  with  numerous  illustrations. 


Hewson  on  Embankments. 

• 

8vo.    Cloth.     $2.00. 

PRINCIPLES   AND    PRACTICE  OF  EMBANKING   LANDS 

from  River  Floods,  as  applied  to  the  Levees  of  the  Mississippi. 
By  WILLIAM  HEWSON,  Civil  Engineer. 

"  This  is  a  valuable  treatise  on  the  principles  and  practice  of  embanking 
lands  from  river  floods,  as  applied  to  the  Levees  of  the  Mississippi,  by  a  highly 
intelligent  and  experienced  engineer.  The  author  says  it  is  a  first  attempt 
to  reduce  to  order  and  to  rule  the  design,  execution,  and  measurement  of  the 
Levees  of  the  Mississippi.  It  is  a  most  useful  and  needed  contribution  to 
scientific  literature. — Philadelphia  Evening  Journal. 


Griiner  on  Steel. 

8vo.  Cloth.     $3.50. 

THE  MANUFACTURE  OF  STEEL.  By  M.  L.  GRTJNER,  trans 
lated  from  the  French.  By  Lenox  Smith,  A.  M.,  E.  M.,  with  an 
appendix  on  the  Bessemer  Process  in  the  United  States,  by  the 
translator.  Illustrated  by  lithographed  drawings  and  wood-cuts. 

"  The  purpose  of  the  work  is  to  present  a  careful,  elaborate,  and  at  the 
same  time  practical  examination  into  the  physical  properties  of  steel,  as  well 
as  a  description  of  the  new  processes  and  mechanical  appliances  for  its  manufac 
ture.  The  information  which  it  contains,  gathered  from  many  trustworthy 
eources,  will  be  found  of  much  value  to  the  American  steel  manufacturer, 
who  may  thus  acquaint  himself  with  the  results  of  careful  and  elaborate  ex 
periments  in  other  countries,  and  better  prepare  himself  for  successful  com 
petition  in  this  important  industry  with  foreign  makers.  The  fact  that  this 
volume  is  from  the  pen  of  one  of  the  ablest  metallurgists  of  the  present  day, 
cannot  fail,  we  think,  to  secure  for  it  a  favorable  consideration. — Iron  Age. 


D.    VAN  NOSTRAND.  11 


Bauerman  on  Iron. 

12mo.  Cloth.     $2.00. 

TREATISE  ON  THE  METALLURGY  OF  IRON.  Contain- 
ing  outlines  of  the  History  of  Iron  Manufacture,  methods  of 
Assay,  and  analysis  of  Iron  Ores,  processes  of  manufacture  of 
Iron  and  Steel,  etc.,  etc.  By  H.  BATJERITAN.  First  American 
edition.  Revised  and  enlarged,  with  an  appendix  on  the  Martin 
Process  for  making  Steel,  from  the  report  of  Abram  S.  Hewitt. 
Illustrated  with  numerous  wood  engravings. 

"  This  is  an  important  addition  to  the  stock  of  technical  works  published  in 
this  country.  It  embodies  the  latest  facts,  discoveries,  and  processes  con 
nected  with  the  manufacture  of  iron  and  steel,  and  should  be  in  the  hands  of 
every  person  interested  in  the  subject,  as  well  as  in  all  technical  and  scientific 
libraries." — Scientific  American. 


Link  and  Valve  Motions,  by  W.  S. 
Auchincloss. 

8vo.  Cloth.     $3.00. 

APPLICATION  OF  THE  SLIDE  VALVE  and  Link  Motion  to 
Stationary,  Portable,  Locomotive  and  Marine  Engines,  with  new 
and  simple  methods  for  proportioning  the  parts.  By  WILLIAM 
S.  AUCHINCLOSS,  Civil  and  Mechanical  Engineer.  Designed  as 
a  hand-book  for  Mechanical  Engineers,  Master  Mechanics, 
Draughtsmen  and  Students  of  Steam  Engineering.  All  dimen 
sions  of  the  valve  are  found  with  the  greatest  ease  by  means  of 
a  Printed  Scale,  and  proportions  of  the  link  determined  without 
the  assistance  of  a  model.  Illustrated  by  37  wood-cuts  and  21 
lithographic  plates,  together  with  a  copperplate  engraving  of  the 
Travel  Scale. 

All  the  matters  we  have  mentioned  are  treated  with  a  clearness  and  absence 
of  unnecessary  verbiage  which  renders  the  work  a  peculiarly  valuable  one. 
The  Travel  Scale  only  requires  to  be  known  to  be  appreciated.  Mr.  A.  writes 
so  ably  on  his  subject,  we  wish  he  had  written  more.  London  En 
gineering. 

We  have  never  opened  a  work  relating  to  steam  which  seemed  to  us  better 
calculated  to  give  an  intelligent  mind  a  clear  understanding  of  the  depart 
ment  it  discusses. — Scientific  American. 


12  SCIENTIFIC  BOOKS  PUBLISHED  BY 

Slide  Valve  by  Eccentrics,  by  Prof. 
C,  W.  MacCord. 

4to.    Illustrated.    Cloth,    $4.00. 

A  PEACTICAL  TEEATISE  ON  THE  SLIDE  YALYE  BY 
ECCENTRICS,  examining  by  methods,  the  action  of  the  Eccen 
tric  upon  the  Slide  Yalve,  and  explaining  the  practical  proces 
ses  of  laying  out  the  movements,  adapting  the  valve  for  its 
various  duties  in  the  steam-engine.  For  the  use  of  Engineers, 
Draughtsmen,  Machinists,  and  Students  of  valve  motions  in 
general.  By  C.  \V.  MAcCoRD,  A.  M.,  Professor  of  Mechanical 
Drawing,  Stevens'  Institute  of  Technology,  Hoboken,  N  J. 


Stillxnan's  Steam-Engine  Indicator. 

12iao.  Cloth.     $1.00. 

THE  STEAM-ENGINE  INDICATOR,  and  the  Improved  Mano 
meter  Steam  and  Vacuum  Gauges ;  their  utility  and  application 
By  PAUL  STILLMAN.  New  edition. 


Bacon's  Steam-Engine  Indicator. 

12mo.  Cloth.     $1.00.     Mor.     $1.50. 

A  TREATISE  ON  THE  RICHARDS  STEAM-ENGINE  IN 
DICATOR,  with  directions  for  its  use.  By  CHARLES  T.  PORTER. 
Revised,  with  notes  and  large  additions  as  developed  by  Amer 
ican  Practice,  with  an  Appendix  containing  useful  formulae  and 
rules  for  Engineers.  By  F.  W.  BACON,  M.  E.,  Member  of  the 
American  Society  of  Civil  Engineers.  Illustrated. 

In  this  work,  Mr.  Porter's  book  has  been  taken  as  the  basis,  but  Mr.  Bacon 
has  adapted  it  to  American  Practice,  and  has  conferred  a  great  boon  on 
American  Engineers. — Artisan. 


Bartol  on  Marine  Boilers. 

8vo.  Cloth.    $1.50. 

TREATISE  ON  THE  MARINE  BOILERS  OF  THE  UNITED 
STATES.     By  H.  B.  BARTOL.     Illustrated. 


D.   VAN  NOSTRAND.  13 

Gillmore's  Limes  and  Cements. 

Fourth  Edition.    Jtevise'l  and  Enlargd. 

8vo.     Cloth.     $4.00. 

PKACTICAL  TEEATISE  ON  LIMES,  HYDEAULIC  CE 
MENTS,  AND  MOETAES.  Papers  on  Practical  Engineering, 
U.  S.  Engineer  Department,  No.  9,  containing  Eeports  of 
numerous  experiments  conducted  in  New  York  City,  during  the 
years  1858  to  1861,  inclusive.  By  Q.  A.  GILLMORE,  Brig-General 
U.  S.  Volunteers,  and  Major  U.  S.  Corps  of  Engineers.  With 
numerous  illustrations. 

"  This  -work  contains  a  record  of  certain  experiments  and  researches  made 
under  the  authority  of  the  Engineer  Bureau  of  the  War  Department  from 
1858  to  1861,  upon  the  various  hydraulic  cements  of  the  United  States,  and 
the  materials  for  their  manufacture.  The  experiments  were  carefully  made, 
and  are  well  reported  and  compiled. ' — Journal  Franklin  Institute. 


Gillmore's  Ooignet  Beton. 

8vo.     Cloth.     $2.50. 

COIGNET   BETON  AND  OTHEE  AETIFICIAL  STONE.     By 
Q,.  A.  GILLMOEE.     9  Plates,  Views,  etc. 

This  work  describes  with  considerable  minuteness  of  detail  the  several  kinds 
of  artificial  stone  in  most  general  use  in  Europe  and  now  beginning  to  be 
introduced  in  the  United  States,  discusses  their  properties,  relative  merits, 

and  cost,  and  describes  the  materials  of  which  they  are  composed 

The  subject  is  one  of  special  and  growing  interest,  and  we  commend  the  work, 
embodying  as  it  does  the  matured  opinions  of  an  experienced  engineer  and 
expert. 


Williamson's  Practical  Tables. 

4to.     Flexible  Cloth.     $2.50. 

PEACTICAL  TABLES  IN  METEOEOLOGY  AND  HYPSO- 
METEY,  in  connection  with  the  use  of  the  Barometer.  By  Col. 
E.  S.  WILLIAMSOM,  U.  S.  A. 


14          SCIENTIFIC  BOOKS  PUBLISHED  BY 

» 

Williamson  on  the  Barometer. 

4to.     Cloth.     $15.00. 

ON  THE  USE  OF  THE  BAKOMETEK  ON  SUKYEYS  AND 
EECONNAISSANCES.  Part  I.  Meteorology  in  its  Connec 
tion  with  Hypsometry.  Part  II.  Barometric  Hypsometry.  By 
E.  S.  WILLIAMSON,  Bvt,  Lieut-Col.  U.  S.  A.,  Major  Corps  of 
Engineers.  With  Illustrative  Tables  and  Engravings.  Paper 
No.  15,  Professional  Papers,  Corps  of  Engineers. 

"  SAN  FRANCISCO,  CAI,.,  Feb.  27, 1867. 
"  Gen.  A.  A.  HUMPHREYS,  Chief  of  Engineers,  U.  S.  Army  : 

"  GENERAL, — I  have  the  honor  to  submit  to  you,  in  the  following  pages,  the 
results  of  my  investigations  in  meteorology  and  hypsometry,  made  with  the 
view  of  ascertaining  how  far  tho  barometer  can  be  used  as  a  reliable  instru 
ment  for  determining  altitudes  on  extended  lines  of  survey  and  reconnais 
sances.  These  investigations  have  occupied  the  leisure  permitted  me  from  my 
professional  duties  during  the  last  ten  years,  and  I  hope  the  results  will  be 
deemed  of  sufficient  value  to  have  a  place  assigned  them  among  the  printed 
professional  papers  of  the  United  States  Corps  of  Engineers. 
"  Very  respectfully,  your  obedient  servant, 

"R.  S.  WILLIAMSON, 
"Brt.  Lt.-Col.  U.  S,  A.,  Major  Corps  of  U.  S.  Engineers." 


Yon  Cotta's  Ore  Deposits. 

8vo.     Cloth.     $4.00. 

TEEATISE  ON  OEE  DEPOSITS.  By  BEBNHAED  VON  COTTA, 
Professor  of  Geology  in  the  Hoyal  School  of  Mines,  Preidberg, 
Saxony.  Translated  from  the  second  German  edition,  by 
FREDERICK  PRIME,  Jr.,  Mining  Engineer,  and  revised  by  the 
author,  with  numerous  illustrations. 

"  Prof.  Von  Cotta  of  the  Freiberg  School  of  Mines,  is  the  author  of  the 
best  modern  treatise  on  ore  deposits,  and  we  are  heartily  glad  that  this  ad 
mirable  work  has  been  translated  and  published  in  this  country.  The  trans 
lator,  Mr.  Frederick  Prime,  Jr.,  a  graduate  of  Freiberg,  has  had  in  his  work 
the  great  advantage  of  a  revision  by  the  author  himself,  who  declares  in  a 
prefatory  note  that  this  may  be  considered  as  a  new  edition  i^the  third)  of  his 
own  book. 

"  It  is  a  timely  and  welcome  contribution  to  the  literature  of  mining  in 
this  country,  and  we  are  grateful  to  the  translator  for  his  enterprise  and  good 
judgment  in  undertaking  its  preparation ;  while  we  recognize  with  equal  cor 
diality  the  liberality  of  the  author  in  granting  both  permission  and  assist 
ance." — Extract  from  Review  in  Engineering  and  Mining  Journal. 


D.  VAST  NOSTJRANJ).  15 

Plattner's  Blow-Pipe  Analysis. 

Second  edition.    Revised,    8vo.    Cloth.    $7.50. 

PLATTNEE'S  MANUAL  OF  QUALITATIVE  AND  QUAN 
TITATIVE  ANALYSIS  WITH  THE  BLOW-PIPE.  From 
the  last  German  edition  Revised  and  enlarged.  By  Prof.  TH. 
RICHTER,  of  the  Royal  Saxon  Mining  Academy.  Translated  by 
Prof.  H.  B.  CORNWALL,  Assistant  in  the  Columbia  School  of 
Mines,  New  York ;  assisted  by  JOHN  H.  CASWELL.  Illustrated 
with  eighty-seven  wood-cuts  and  one  Lithographic  Plate.  560 
pages. 

"  Plattner's  celebrated  work  has  long  been  recognized  as  the  only  complete 
book  on  Blow-Pipe  Analysis.  The  fourth  German  edition,  edited  by  Prof. 
Bichter,  fully  sustains  the  reputation  which  the  earlier  editions  acquired  dur 
ing  the  lifetime  of  the  author,  and  it  ia  a  source  of  great  satisfaction  to  us  to 
know  that  Prof.  Eichter  has  co-operated  with  the  translator  in  issuing  the 
American  edition  of  the  work,  which  is  in  fact  a  fifth  edition  of  the  original 
work,  being  far  more  complete  than  the  last  German-  edition." — SllUmari'a 
Journal. 

There  is  nothing  BO  complete  to  be  found  in  the  English  language.  Platt 
ner's  book  is  not  a  mere  pocket  edition  ;  it  is  iatended  as  a  comprehensive  guide 
to  all  that  is  at  present  known  on  the  blow-pipe,  and  as  such  is  really  indis 
pensable  to  teachers  and  advanced  pupils. 

"  Mr.  Cornwall's  edition  is  something  more  than  a  translation,  as  it  contains 
many  corrections,  emendations  and  additions  not  to  be  found  in  the  original. 
It  is  a  decided  improvement  on  the  work  in  its  German  dress." — Journal  of 
Applied  Chemistry. 


Egleston's  Mineralogy. 

8ro.     Illustrated  with  34  Lithographic  Plates.     Cloth.     $4.50. 

LECTURES  ON  DESCRIPTIVE  MINERALOGY,  Delivered 
at  the  School  of  Mines,  Columbia  College.  Br  PROFESSOR  T. 
EGLESTOX. 

These  lectures  are  what  their  title  indicates,  the  lectures  on  Mineralogy 
delivered  at  the  School  of  Mines  of  Columbia  College.  They  have  beea 
printed  for  the  students,  in  order  that  more  time  might  be  given  to  the  vari 
ous  methods  of  examining  and  determining  minerals.  The  second  part  has 
only  been  printed.  The  first  part,  comprising  crystallography  and  physical 
mineralogy,  will  be  printed  at  some  future  time. 


16  SCIENTIFIC  BOOKS  PUBLISHED  BY 

Pynchon's  Chemical  Physics. 

New  Edition.    Revised  and  Enlarged. 

Crown  8vo.     Cloth.     $3.00. 

INTRODUCTION  TO  CHEMICAL  PHYSICS,  Designed  for  the 
Use  of  Academies,  Colleges,  and  High  Schools.  Illustrated  with 
numerous  engravings,  and  containing  copious  experiments  with 
directions  for  preparing  them.  By  THOMAS  RUGGLES  PYXCHON, 
M.A.,  Professor  of  Chemistry  and  the  Natural  Sciences,  Trinity 
College,  Hartford. 

Hitherto,  no  work  suitable  for  general  use,  treating  of  all  these  subjects 
within  the  limits  of  a  single  volume,  could  be  found ;  consequently  the  atten 
tion  they  have  received  has  not  been  at  all  proportionate  to  their  importance. 
It  is  believed  that  a  book  containing  so  much  valuable  information  within  so 
small  a  compass,  cannot  fail  to  meet  with  a  ready  sale  among  all  intelligent 
persons,  while  Professional  men,  Physicians,  Medical  Students,  Photograph 
ers,  Telegraphers,  Engineers,  and  Artisans  generally,  will  find  it  specially 
valuable,  if  not  nearly  indispensable,  as  a  book  of  reference. 

"  We  strongly  recommend  this  able  treatise  to  our  readers  as  the  first 
work  ever  published  on  the  subject  free  from  perplexing  technicalities.  In 
style  it  is  pure,  in  description  graphic,  and  its  typographical  appearance  is 
artistic.  It  is  altogether  a  most  excellent  work." — Eclectic  Medical  Journal. 

"  It  treats  fully  of  Photography,  Telegraphy,  Steam  Engines,  and  the 
various  applications  of  Electricity.  In  short,  it  is  a  carefully  prepared 
volume,  abreast  with  the  latest  scientific  discoveries  and  inventions,'' — Hart" 
ford  Courant. 

Plympton's  Blow-Pipe  Analysis. 

12mo.     Cloth.     $2.00. 

THE  BLOW-PIPE  :  A  System  of  Instruction  in  its  practical  use 
being  a  graduated  course  of  Analysis  for  the  use  of  students, 
and  all  those  engaged  in  the  Examination  of  Metallic  Combina 
tions.  Second  edition,  with  an  appendix  and  a  copious  index. 
By  GEORGE  W.  PLYMPTON,  of  the  Polytechnic  Institute,  Brooklyn. 

"  This  manual  probably  has  no  superior  in  the  English  language  as  a  text 
book  for  beginners,  or  as  a  guide  to  the  student  working  without  a  teacher. 
To  the  latter  many  illustrations  of  the  utensils  and  apparatus  required  in 
using  the  blow-pipe,  as  well  as  the  fully  illustrated  description  of  the  blow 
pipe  flame,  will  be  especially  serviceable."— New  York  TeacJier. 


D.    VAJST  NOSTEANJ}.  17 


lire's  Dictionary. 

Sixth   Edition. 

London,  1872. 
3  vols.     8vo.     Cloth,  $25.00.     Half  Russia,  $37.50. 

DICTIONARY  OF  ARTS,  MANUFACTURES,  AND  MINES. 
By  AXDEEW  UEE,  M.D.  Sixth  edition.  Edited  by  ROBERT  HUNT, 
F.R.S.,  greatly  enlarged  and  rewritten. 


Brande  and  Cox's  Dictionary, 

New  Edition. 

London,  1872. 
3  rols.    8vo.     Cloth,  $20.00.     Half  Morocco,  $27.50. 

A  Dictionary  of  Science,  Literature,  and  Art.     Edited  by  W.  T. 
BRANDE  and  Rev.  GEO.  W.  Cox.     New  and  enlarged  edition. 


Watt's  Dictionary  of  Chemistry. 

Supplementary  Volume. 

8vo.    Cloth.     $9.00. 

This  volume  brings  the  Record  of  Chemical  Discovery  down  to  the  end  oJ 
the  year  1869,  including  also  several  additions  to,  and  corrections  of,  former 
results  which  have  appeared  in  1870  and  1871. 

*£.*  Complete  Sets  of  the  Work,  New  and  Revised  edition,  including1  above 
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Bammelsberg's  Chemical  Analysis. 

8vo.     Cloth.     $2.25. 

GUIDE  TO  A  COURSE  OF  QUANTITATIVE  CHEMICAL 
ANALYSIS,  ESPECIALLY  OF  MINERALS  AND  FUR 
NACE  PRODUCTS.  Illustrated  by  Examples.  By  C.  F. 
RAMMELSBEKG.  Translated  by  J.  TOWLEK,  M.D. 

This  work  has  been  translated,  and  is  now  published  expressly  for  those 
students  in  chemistry  whose  time  and  other  studies  in  colleges  do  not  permit 
them  to  enter  upon  the  more  elaborate  and  expensive  treatises  of  Fresenius 
and  others.  It  is  the  condensed  labor  of  a  master  in  chemistry  and  of  a  prac 
tical  analyst. 


18          SCIENTIFIC  BOOKS  PUBLISHED  BY 

Eliot  and  Storer's  Qualitative 
Chemical  Analysis. 

New  Edition,  Revised. 

12mo.     Illustrated.     Cloth.     $1.50. 

A  COMPENDIOUS  MANUAL  OF  QUALITATIVE  CHEMI 
CAL  ANALYSIS.  By  CHARLES  W.  ELIOT  and  FRANK  H.  STOKER. 
Revised  with  the  Cooperation  of  the  Authors,  by  WILLIAM  HIP- 
LEY  NICHOLS,  Professor  of  Chemistry  in  the  Massachusetts  Insti 
tute  of  Technology. 

"  This  Manual  has  great  merits  as  a  practical  introduction  to  the  science 
and  the  art  of  which  it  treats.  It  contains  enough  of  the  theory  and  practice 
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volved  in  the  science,  and  to  present  clearly  to  the  student  the  most  approved 
methods  of  the  art.  It  is  specially  adapted  for  exercises  and  experiments  in 
the  laboratory;  and  yet  its  classifications  and  manner  of  treatment  are  so 
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higher  class  of  students  generally  who  desire  an  accurate  knowledge  of  the 
practical  methods  of  arriving  at  scientific  facts." — Lutheran  Observer. 

"  We  wish  every  academical  class  in  the  land  could  have  the  benefit  of  the 
fifty  exercises  of  two  hours  each  necessary  to  master  this  book.  Chemistry 
would  cease  to  be  a  mere  matter  of  memory,  and  become  a  pleasant  experi 
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ital  discipline." — College  Courant. 


Craig's  Decimal  System. 

Square    32mo.     Limp.     50c. 

WEIGHTS  AND  MEASUEES.  An  Account  of  the  Decimal 
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Uses.  By  B,  F.  CRAIG,  M.  D. 

"  The  most  lucid,  accurate,  and  useful  of  all  the  hand-books  on  this  subject 
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English  and  French  denominations  of  length,  area,  capacity,  weight,  and  the 
Centigrade  and  Fahrenheit  thermometers,  with  clear  instructions  how  to  use 
them ;  and  to  this  practical  portion,  which  helps  to  make  the  transition  as 
easy  as  possible,  is  prefixed  a  scientific  explanation  of  the  errors  in  the  metric 
system,  and  how  they  may  be  corrected  in  the  laboratory." — Nation. 


I).   VAN  NOSTRAFD.  19 

Nugent  on  Optics. 

12mo.      Cloth.     $2.00 

TREATISE  ON  OPTICS ;  or,  Light  and  Sight,  theoretically  and 
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illustrations. 

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cations  of  the  science." — Round  Table. 


Barnard's  Metric  System. 

8vo.     Brown  cloth.     $3.00. 

THE   METRIC  SYSTEM  OF  WEIGHTS   AND  MEASURES. 

An  Address  delivered  before  the  Convocation  of  the  University  of 
the  State  of  New  York,  at  Albany,  August,  1871.  By  FREDERICK 
A.  P.  BARNARD,  President  of  Columbia  College,  New  York  City. 
Second  edition  from  the  Revised  edition  printed  for  the  Trustees 
of  Columbia  College.  Tinted  paper. 

"  It  is  the  best  summary  of  the  arguments  in  favor  of  the  metric  weights 
and  measures  with  which  we  are  acquainted,  not  only  because  it  contains  in 
small  space  the  leading  facts  of  the  case,  but  because  it  puts  the  advocacy  of 
that  system  on  the  only  tenable  grounds,  namely,  the  great  convenience  of  a 
decimal  notation  of  weight  and  measure  as  well  as  money,  the  value  of  inter 
national  uniformity  in  the  matter,  and  the  fact  that  this  metric  system  is 
adopted  and  in  general  use  by  the  majority  of  civilized  nations." — The  Notion. 


The  Young  Mechanic. 

Illustrated.     12mo.     Cloth.     $1.75. 

THE  YOUNG  MECHANIC.  Containing  directions  for  the  use 
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and  mechanical  models,  including  the  Art  of  Turning  in  Wood 
and  Metal.  By  the  author  of  "The  Lathe  and  its  Uses,"  etc 
From  the  English  edition,  with  corrections. 


20  SCIENTIFIC  BOOKS  PUBLISHED  BY 

Harrison's  Mechanic's  Tool-Book. 

12mo.     Cloth.     $1.50. 

MECHANIC'S  TOOL  BOOK,  with  practical  rules  and  suggestions, 
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HARRISON,  Associate  Editor  of  the  "  American  Artisan."  Illustra 
ted  with  44  engravings. 

"  This  work  is  specially  adapted  to  meet  the  wants  of  Machinists  and  work 
ers  in  iron  generally.  It  is  made  up  of  the  work-day  experience  of  an  intelli 
gent  and  ingenious  mechanic,  who  had  the  faculty  of  adapting  tools  to  various 
purposes.  The  practicability  of  his  plans  and  suggestions  are  made  apparent 
even  to  the  unpractised  eye  by  a  series  of  well-executed  wood  engravings." — 
Philadelphia  Inquirer. 

Pope's  Modern  Practice  of  the  Elec 
tric  Telegraph. 

Seventh  edition.    8vo.    Cloth     $2.00. 

A  Hand-book  for  Electricians  and  Operators.  By  FKANK  L.  POPE. 
Seventh  edition.  Revised  and  enlarged,  and  fully  illustrated. 

Extract  from  Letter  of  Prof.  Morse. 

"  I  have  had  time  only  cursorily  to  examine  its  contents,  but  this  examina 
tion  has  resulted  in  great  gratification,  especially  at  the  fairness  and  unpre 
judiced  tone  of  your  whole  work. 

"  Your  illustrated  diagrams  are  admirable  and  beautifully  executed. 

"  I  think  all  your  instructions  in  the  use  of  the  telegraph  apparatus  judi 
cious  and  correct,  and  I  most  cordially  wish  you  success." 

Extract  from  Letter  of  Prof.  G.  W.  Hough,  of  the  Dudley  Observatory. 

"  There  is  no  other  work  of  this  kind  in  the  English  language  that  con 
tains  in  so  small  a  compass  so  much  practical  information  in  the  application 
of  galvanic  electricity  to  telegraphy.  It  should  be  in  the  hands  of  every  one 
interested  in  telegraphy,  or  the  use  of  Batteries  for  other  purposes." 


Morse's  Telegraphic  Apparatus. 

Illustrated.     8vo.     Cloth.     $2.00. 

EXAMINATION  OF  THE  TELEGRAPHIC  APPAEATUS 
AND  THE  PROCESSES  IN  TELEGAPHY.  By  SAMUEL  F. 
B.  MORSE,  LL.D.,  United  States  Commissioner  Paris  Universal 
Exposition,  1867. 


D.  VAN'  NOSTRAND.  21 

Sabine's  History  of  the  Telegraph. 

12mo.  Cloth.     $1.25. 

HISTOKY  AND  PROGRESS  OF  THE  ELECTRIC  TELE 
GRAPH,  with  Descriptions  of  some  of  the  Apparatus.  By 
ROBERT  SA.BINE,  C.  E.  Second  edition,  with  additions. 

CONTENTS. — I.  Early  Observations  of  Electrical  Phenomena.  II.  Tele 
graphs  by  Frictional  Electricity.  III.  Telegraphs  by  Voltaic  Electricity. 
IV.  Telegraphs  by  Electro-Magnetism  and  Magneto-Electricity.  V.  Tele 
graphs  now  in  use.  VI.  Overhead  Lines.  VII.  Submarine  Telegraph  Lines. 
VIII.  Underground  Telegraphs.  IX.  Atmospheric  Electricity. 


Shaffner's  Telegraph  Manual. 

8vo.     Cloth.    $6.50. 

A  COMPLETE  HISTORY  AND  DESCRIPTION  OF  THE 
SEMAPHORIC,  ELECTRIC,  AND  MAGNETIC  TELE 
GRAPHS  OF  EUROPE,  ASIA,  AFRICA,  AND  AMERICA, 
with  625  illustrations.  By  TAL.  P.  SHAFFNER,  of  Kentucky. 
New  edition. 

Onlley's  Hand-Book  of  Telegraphy. 

8vo.     Cloth.     $5.00. 

A  HAND-BOOK  OF  PRACTICAL  TELEGRAPHY.      By  R.  S. 

CULLEY,  Engineer  to   the  Electric  and  International  Telegraph 
Company.     Fourth  edition,  revised  and  enlarged. 


Foster's  Submarine  Blasting. 

4to.     Cloth.     $3.50. 

SUBMARINE  BLASTING  in  Boston  Harbor,  Massachusetts- 
Removal  of  Tower  and  Corwin  Rocks.  By  JOHN  G.  FOSTEB, 
Lieutenant-Colonel  of  Engineers,  and  Brevet  Major- General,  U. 
S.  Army.  Illustrated  with  seven  plates* 

LIST  OP  PLATES. — 1.  Sketch  of  the  Narrows,  Boston  Harbor.  2. 
Townsend's  Submarine  Drilling  Machine,  and  Working  Vessel  attending. 
3.  Submarine  Drilling  Machine  employed.  4.  Details  of  Drilling  Machine 
employed.  5.  Cartridges  and  Tamping  used.  6.  Fuses  and  Insulated  Wires 
used.  7.  Portable  Friction  Battery  used. 


22  SCIENTIFIC  BOOKS  PUBLISHED  BY 

Barnes'  Submarine  Warfare. 

8vo.     Cloth.     $5.00. 

SUBMAEINE  WARFARE,  DEFENSIVE  AND  OFFENSIVE. 
Comprising  a  full  and  complete  History  of  the  Invention  of  the 
Torpedo,  its  employment  in  War  and  results  of  its  use.  De 
scriptions  of  the  yarious  forms  of  Torpedoes,  Submarine  Batteries 
and  Torpedo  Boats  actually  used  in  War.  Methods  of  Ignition 
by  Machinery,  Contact  Fuzes,  and  Electricity,  and  a  full  account 
of  experiments  made  to  determine  the  Explosive  Force  of  Gun 
powder  under  Water.  Also  a  discussion  of  the  Offensive  Torpedo 
system,  its  effect  upon  Iron-Clad  Ship  systems,  and  influence  upon 
Future  Naval  Wars.  By  Lieut-Commander  JOHN  S.  BABXES, 
U.  S.  N.  With  twenty  lithographic  plates  and  many  wood-cuts. 

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engines  that  have  been  contrived  for  submarine  hostilities,  including-  a  discus 
sion  of  the  torpedo  system,  its  effects  upon  iron-clad  ship-systems,  and  its 
probable  influence  upon  future  naval  wars.  Plates  of  a  valuable  character 
accompany  the  treatise,  which  affords  a  useful  history  of  the  momentous  sub 
ject  it  discusses.  A  great  deal  of  useful  information  is  collected  in  its  pages, 
especially  concerning  the  inventions  of  SCHOLL  and  VEIIDU,  and  of  JONES' 
and  HUNT'S  batteries,  as  well  as  of  other  similar  machines,  and  the  use  in 
submarine  operations  of  gun-cotton  and  nitro-glycerme." — N.  T.  Times. 


Randall's  Quartz  Operator's  Hand- 

Book. 

12mo.     Cloth.     $2.00. 

QUARTZ  OPERATOR'S   HAND-BOOK.     By   P.  M.  RANDALL. 
New  edition,  revised  and  enlarged.     Fully  illustrated. 

The  object  of  this  work  has  been  to  present  a  clear  and  comprehensive  ex 
position  of  mineral  veins,  and  the  means  and  modes  chiefly  employed  for  the 
mining  and  working  of  their  ores — more  especially  those  containing  gold  and 
silver. 


D.    VAN  NOSTRAND.  23 

MitcheH's  Manual  of  Assaying. 

8vo.     Cloth.     $10.00. 

A  MANUAL  OF  PRACTICAL  ASSAYING.    By  JOHN  MITCHELL. 
Third  edition.     Edited  by  WILLIAM  CROOKES,  F.R.S. 

In  this  edition  are  incorporated  all  the  late  important  discoveries  in  Assay 
ing  made  in  this  country  and  abroad,  and  special  care  is  devoted  to  the  very 
important  Volumetric  and  Colorimetric  Assays,  as  well  as  to  the  Blow-Pipe 


Benet's  Chronoscope. 

Second  Edition. 

Illustrated.     4to.     Cloth.     $3.00. 

ELECTRO-BALLISTIC  MACHINES,  and  the  Schultz  Chrono 
scope.  By  Lieutenant-Colonel  S.  V.  BENET,  Captain  of  Ordnance, 
U.  S.  Army. 

CONTENTS. — 1.  Ballistic  Pendulum.  2.  Gun  Pendulum.  3.  Use  of  Elec 
tricity.  4.  Navez' Machine.  5.  Vignotti's  Machine,  with  Plates.  6.  Benton's 
Electro-Ballistic  Pendulum,  with  Plates.  7.  Leur's  Tro-Pendulum  Machine 
8.  Schultz's  Chronoscope,  with  two  Plates. 


Michaelis'  Chronograph. 

4to.     Illustrated.     Cloth.     $3.00. 

THE  LE  BOITLENGE  CHRONOGRAPH.  With  three  litho 
graphed  folding  plates  of  illustrations.  By  Brevet  Captain  0  E. 
MICHAELIS,  First  Lieutenant  Ordnance  Corps,  U.  S.  Army. 

"  The  excellent  monograph  of  Captain  Michaelis  enters  minutely  into  tho 
details  of  construction  and  management,  and  gives  tables  of  the  tirr.es  of  flight 
calculated  upon  a  given  fall  of  the  chronometer  for  all  distances.  Captain 
Michaelis  has  done  good  service  in  presenting  this  work  to  his  brother  officers, 
describing,  as  it  does,  an  instrument  which  bids  fair  to  be  in  constant  use  in 
our  future  ballistic  experiments.'  —Army  and  Navy  Journal. 


24          SCIENTIFIC  BOOKS  PUBLISHED  BY 

Silversmith's  Hand-Book. 

Fourth  Edition. 

Illustrated.     12mo.     Cloth.     $3.00. 

A  PEACTICAL  HAND-BOOK  FOE  MINERS,  Metallurgists, 
and  Assayers,  comprising  the  most  recent  improvements  in  the 
disintegration,  amalgamation,  smelting,  and  parting  of  the 
Precious  Ores,  with  a  Comprehensive  Digest  of  the  Mining 
Laws.  Greatly  augmented,  revised,  and  corrected.  By  JULIUS 
SILVERSMITH.  Fourth  edition.  Profusely  illustrated.  1  vol. 
12mo.  Cloth.  $3.00. 

One  of  the  most  important  features  of  this  work  is  that  in  which  the 
metallurgy  of  the  precious  metals  is  treated  of.  In  it  the  author  has  endeav 
ored  to  embody  all  the  processes  for  the  reduction  and  manipulation  of  the 
precious  ores  heretofore  successfully  employed  in  Germany,  England,  Mexico, 
and  the  United  States,  together  with  such  as  have  been  more  recently  invented, 
and  not  yet  fully  tested — all  of  which  are  profusely  illustrated  and  easy  of 
comprehension. 


Simms'  Levelling. 

8vo.     Cloth.     $2.50. 

A  TREATISE  ON  THE  PEINCIPLES  AND  PRACTICE  OF 
LEVELLING,  showing  its  application  to  purposes  of  Railway 
Engineering  and  the  Construction  of  Roads,  &c.  By  FREDERICK 
W.  SIMMS,  C.  E.  From  the  fifth  London  edition,  revised  and 
corrected,  with  the  addition  of  Mr.  Law's  Practical  Examples  for 
Setting  Out  Railway  Curves.  Illustrated  with  three  lithographic 
plates  and  numerous  wood-cuts. 

"  One  of  the  most  important  text-books  for  the  general  surveyor,  and  there 
is  scarcely  a  question  connected  with  levelling  for  which  a  solution  would  be 
sought,  but  that  would  be  satisfactorily  answered  by  consulting  this  volume." 
— Mining  Journal. 

"  The  text-book  on  levelling  in  most  of  our  engineering  schools  and  col 
leges." — Engineers. 

"The  publishers  have  rendered  a  substantial  service  to  the  profession, 
especially  to  the  younger  members,  by  bringing  out  the  present  edition  of 
Mr.  Simms'  useful  work." — Engineering. 


D.  VAN  NO  STRAND.  25 

Eads'  Naval  Defences. 

4to.     Cloth.    $5.00. 

SYSTEM  OF  NAVAL  DEFENCES.  By  JAMES  B.  EADS,  C.  E. 
Report  to  the  Honorable  Gideon  Welles,  Secretary  of  the  Navy, 
February  22,  1868,  with  ten  illustrations. 


Stuart's  Naval  Dry  Docks. 

Twenty-four  engravings  on  steel. 
Fourth  Edition. 
4to.    Cloth.    $6.00. 

THE  NAVAL  DRY  DOCKS  OF  THE  UNITED  STATES. 
By  CHAELES  B.  STUART.  Engineer  in  Chief  of  the  United  States 
Navy. 

List  of  Illustrations. 

Pumping  Engine  and  Pumps — Plan  of  Dry  Dock  and  Pump- Well  -  Sec 
tions  of  Dry  Dock — Engine  House— Iron  Floating  Gate — Details  of  Floating 
Gate — Iron  Turning  Gate — Plan  of  Turning  Gate — Culvert  Gate — Filling 
Culvert  Gates — Engine  Bed — Plate,  Pumps,  and  Culvert — Engine  House 
Roof— Floating  Sectional  Dock— Details  of  Section,  and  Plan  of  Turn-Tables 
— Plan  of  Basin  and  Marine  Railways — Plan  of  Sliding  Frame,  and  Elevation 
of  Pumps — Hydraulic  Cylinder — Plan  of  Gearing  for  Pumps  and  End  Floats 
— Perspective  View  of  Dock,  Basin,  and  Railway — Plan  of  Basin  of  Ports 
mouth  Dry  Dock — Floating  Balance  Dock — Elevation  of  Trusses  and  the  Ma 
chinery—  Perspective  View  of  Balance  Dry  Dock 


Free  Hand  Drawing. 

Profusely  Illustrated.     18mo.     Cloth.     75  cents. 

A  GUIDE  TO  ORNAMENTAL,  Figure,   and  Landscape  Draw 
ing.     By  an  Art  Student. 

CONTENTS. — Materials  employed  in  Drawing,  and  how  to  use  them — On 
Lines  and  how  to  Draw  them — On  Shading — Concerning  lines  and  shading, 
with  applications  of  them  to  simple  elementary  subjects — Sketches  from  Na 
ture. 


26  SCIENTIFIC  BOOKS  PUBLISHED  BY 

Minified  Mechanical  Drawing. 

Eighth  Edition. 

Royal  8vo.     Cloth.     $4.00. 

A  TEXT-BOOK  OF  GEOMETRICAL  DRAWING  for  the  use 
of  Mechanics  and  Schools,  in  which  the  Definitions  and  Rules  of 
Geometry  are  familiarly  explained  ;  the  Practical  Problems  are 
arranged,  from  the  most  simple  to  the  more  complex,  and  in  their 
description  technicalities  are  avoided  as  much  as  possible.  With 
illustrations  for  Drawing  Plans,  Sections,  and  Elevations  of 
Buildings  and  Machinery ;  an  Introduction  to  Isometrical  Draw 
ing,  and  an  Essay  on  Linear  Perspective  and  Shadows.  Illus 
trated  with  over  200  diagrams  engraved  on  steel.  By  WM. 
MINIFIE,  Architect.  Eighth  Edition.  With  an  Appendix  on  the 
Theory  and  Application  of  Colors. 

"  It  is  the  best  work  on  Drawing  that  we  have  ever  seen,  and  is  especially  a 
text-book  ox  Geometrical  Drawing  for  the  use  of  Mechanics  and  Schools.  No 
young  Mechanic,  such  as  a  Machinist,  Engineer,  Cabinet-Maker,  Millwright, 
or  Carpenter,  should  be  without  it." — Scientific  American. 

"  One  of  the  most  comprehensive  works  of  the  kind  ever  published,  and  can 
not  but  possess  great  value  to  builders.  The  style  is  at  once  elegant  and  sub 
stantial.  ' — Pennsylvania  Inquirer. 

"  Whatever  is  said  is  rendered  perfectly  intelligible  by  remarkably  well- 
executed  diagrams  on  steel,  leaving  nothing  for  mere  vague  supposition ;  and 
the  addition  of  an  introduction  to  isometrical  drawing,  linear  perspective,  and 
the  projection  of  shadows,  winding  up  with  a  \iseful  index  to  technical  terms." 
— Glasgow  Mechanics'  Journal. 

^W  The  British  Government  has  authorized  the  use  of  this  book  in  their 
schools  of  art  at  Somerset  House,  London,  and  throughout  the  kingdom. 


Minifle's  Geometrical  Drawing. 

New  Edition.    Enlarged. 

12mo.     Cloth.     $2.00. 

GEOMETRICAL  DEAWING.  Abridged  from  the  octavo  edition, 
for  the  use  of  Schools.  Illustrated  with  48  steel  plates.  New 
edition,  enlarged. 

"  It  is  well  adapted  as  a  text-book  of  drawing  to  be  used  in  our  High  Schools 
and  Academies  where  this  useful  branch  of  the  fine  arts  has  been,  hitherto  too 
much  neglected." — Boston  Journal. 


D.   VAN  NOSTRAND.  27 

Bell  on  Iron  Smelting. 

8vo.     Cloth.     $6.00. 

CHEMICAL  PHENOMENA  OF  IEON  SMELTING.  An  ex 
perimental  and  practical  examination  of  the  circumstances  which 
determine  the  capacity  of  the  Blast  Furnace,  the  Temperature 
of  the  Air,  and  the  Proper  Condition  of  the  Materials  to  be 
operated  upon.  By  I.  LOWTHIAN  BELL. 

"  The  reactions  which  take  place  in  every  foot  of  the  blast-furnace  have 
been  investigated,  and  the  nature  of  every  step  in  the  process,  from  the  intro 
duction  of  the  raw  material  into  the  furnace  to  the  production  of  the  pig  iron, 
has  been  carefully  ascertained,  and  recorded  so  fully  that  any  one  in  the  trade 
can  readily  avail  themselves  of  the  knowledge  acquired ;  and  we  have  no  hes 
itation  in  saying  that  the  judicious  application  of  such  knowledge  will  do 
much  to  facilitate  the  introduction  of  arrangements  which  will  still  further 
economize  fuel,  and  at  the  same  time  permit  of  the  quality  of  the  resulting 
metal  being  maintained,  if  not  improved.  The  volume  is  one  which  no  prac 
tical  pig  iron  manufacturer  can  afford  to  be  without  if  he  be  desirous  of  en 
tering  upon  that  competition  which  nowadays  is  essential  to  progress,  and 
in  issuing  such  a  work  Mr.  Bell  has  entitled  himself  to  the  best  thanks  of 
every  member  of  the  trade." — London  Mining  Journal. 


King's  Notes  on  Steam. 

TJiirteenth  Edition. 

8vo.     Cloth.     $2.00. 

LESSONS  AND  PEACTICAL  NOTES  ON  STEAM,  the  Steam- 
Engine,  Propellers,  &c.,  &c.,  for  Young  Engineers,  Students,  and 
others.  By  the  late  W.  E.  KING,  U.  S.  N.  Eevised  by  Chief- 
Engineer  J.  W.  KING,  U.  S.  Navy. 

"  This  is  one  of  the  best,  because  eminently  plain  and  practical  treatises  on 
the  Steam  Engine  ever  published. ' — Philadelphia  Press. 

This  is  the  thirteenth  edition  of  a  valuable  work  of  the  late  W.  H.  King, 
U.  S.  N.  It  contains  lessons  and  practical  notes  on  Steam  and  the  Steam  En 
gine,  Propellers,  etc.  It  is  calculated  to  be  of  great  use  to  young  marine  en 
gineers,  students,  and  others.  The  text  is  illustrated  and  explained  by  nu 
merous  diagrams  and  representations  of  machinery.  —Boston  Daily  Adver 
tiser. 

Text-book  at  the  U.  S.  Naval  Academy,  Annapolis. 


28  SCIENTIFIC  BOOKS  PUBLISHED  B  Y 

Burgh's  Modern  Marine  Engineering. 

One  thick  4to  vol.     Cloth.     $25.00.     Half  morocco.     $30.00. 

MODERN  MARINE  ENGINEERING,  applied  to  Paddle  and 
Screw  Propulsion.  Consisting  of  3G  Colored  Plates,  259  Practical 
Wood-cut  Illustrations,  and  403  pages  of  Descriptive  Matter,  the 
whole  being  an  exposition  of  the  present  practice  of  the  follow 
ing  firms  :  Messrs.  J.  Penn  &  Sons ;  Messrs.  Maudslay,  Sons  & 
Field ;  Messrs.  James  Watt  &  Co. ;  Messrs.  J.  &  Gr.  Rennie ; 
Messrs.  R.  Napier  &  Sons  ;  Messrs.  J.  &  W.  Dudgeon  ;  Messrs. 
Ravenhill  &  Hodgson ;  Messrs.  Humphreys  &  Tenant ;  Mr. 
J.  T.  Sponcer,  and  Messrs.  Forrester  &  Co.  By  N.  P.  BUEGH, 
Engineer. 

PRINCIPAL,  CONTENTS. — General  Arrangements  of  Engines,  11  examples 
— General  Arrangement  of  Boilers,  14  examples  —  General  Arrangement  of 
Superheaters,  11  examples — Details  of  'Oscillating  Paddle  Engines,  34  ex 
amples — Condensers  for  Screw  Engines,  both  Injection  and  Surface,  20  ex 
amples — Details  of  Screw  Engines,  20  examples — Cylinders  and  Details  of 
Screw  Engines,  21  examples — Slide  Valves  and  Details,  7  examples — Slide 
Valve,  Link  Motion,  7  examples  —  Expansion  Valves  and  Gear,  10  exam 
ples — Details  in  General,  30  examples  —  Sere w  Propeller  and  Fittings,  13  ex 
amples  Engine  and  Boiler  Fittings,  28  examples  -  In  relation  to  the  Princi 
ples  of  the  Marine  Engine  and  Boiler,  33  examples. 

Notices  of  the  Press. 

"Every  conceivable  detail  of  the  Marine  Engine,  under  all  its  various 
forms,  is  profusely,  and  we  must  add,  admirably  illustrated  by  a  multitude 
of  engravings,  selected  from  the  best  and  most  modern  practice  of  tlie  first 
Marine  Engineers  of  the  day.  The  chapter  on  Condensers  is  peculiarly  valu 
able.  In  one  word,  there  is  no  other  work  in  existt  nee  which  will  bear  a 
moment's  comparison  with  it  as  an  exponent  of  the  skill,  talent  and  practical 
experience  to  which  is  due  the  splendid  reputation  enjoyed  by  many  British 
Marine  Engineers."  —  Engineer. 

"  This  very  comprehensive  work,  which  was  issued  in  Monthly  parts,  has 
just  been  completed.  It  contains  large  and  full  drawings  and  copious  de 
scriptions  of  most  of  the  best  examples  of  Modern  Marine  Engines,  and  it  is 
a  complete  theoretical  and  practical  treatise  on  the  subject  of  Marine  Engi 
neering." — American  Artisan. 

This  is  the  only  edition  of  tho  above  -work  with  the  beautifully  colored 
plates,  and  it  is  out  of  print  in  England. 


D.   VAN  NOSTRAND.  29 

Bourne's  Treatise  on  the  Steam  En 
gine. 

Ninth  Edition. 

Illustrated.     4to.     Cloth.     $15.00. 

TREATISE  ON  THE  STEAM  ENGINE  in  its  various  applica 
tions  to  Mines,  Mills,  Steam  Navigation,  Railways,  and  Agricul 
ture,  with  the  theoretical  investigations  respecting  the  Motive 
Power  of  Heat  and  the  proper  Proportions  of  Steam  Engines. 
Elaborate  Tables  of  the  right  dimensions  of  every  part,  and 
Practical  Instructions  for  the  Manufacture  and  Management  of 
every  species  of  Engine  in  actual  use.  By  JOHN  BOURNE,  being 
the  ninth  edition  of  "  A  Treatise  on  the  Steam  Engine,"  by 
the  "Artisan  Club."  Illustrated  by  thirty-eight  plates  and  five 
hundred  and  forty-six  wood-cuts. 

As  Mr.  Bourne's  work  has  the  great  merit  of  avoiding  unsound  and  imma 
ture  views,  it  may  safely  be  consulted  by  all  who  are  really  desirous  of  ac 
quiring  trustworthy  information  on  the  subject  of  which  it  treats.  During 
the  twenty-two  years  which  have  elapsed  from  the  issue  of  the  first  edition, 
the  improvements  introduced  in  the  construction  of  the  steam  engine  have 
been  both  numerous  and  important,  and  of  these  Mr.  Bourne  has  taken  care 
to  point  out  the  more  prominent,  and  to  furnish  the  reader  with  such  infor 
mation  as  shall  enable  him  readily  to  judge  of  their  relative  value.  This  edi 
tion  has  been  thoroughly  modernized,  and  made  to  accord  with  the  opinions 
and  practice  of  the  more  successful  engineers  of  the  present  day.  All  that 
the  book  professes  to  give  is  given  with  ability  and  evident  care.  The  scien 
tific  principles  which  are  permanent  are  admirably  explained,  and  reference 
is  made  to  many  of  the  more  valuable  of  the  recently  introduced  engines.  To 
express  an  opinion  of  the  value  and  utility  of  such  a  work  as  The  Artisan 
CluUs  Treatise  on  the  Steam  Engine,  which  has  passed  through  eight  editions 
already,  would  be  superfluous ;  but  it  may  be  safely  stated  that  the  work  is 
worthy  the  attentive  study  of  all  either  engaged  in  the  manufacture  of  steam 
engines  or  interested  in  economizing  the  use  of  steam. —  Mining  Journal. 


Isherwood's  Engineering  Precedents. 

Two  Vols.  in  One.     8vo.     Cloth.     $2.50. 

ENGINEERING  PEECEDENTS  FOR  STEAM  MACHINERY. 

Arranged  in  the  most  practical  and  useful  manner  for  Engineers. 
By  B.  F.  ISHERWOOD,  Civil  Engineer,  U.  S.  Navy.  "With  illus 
trations. 


30 


SCIENTIFIC  BOOKS  PUBLISHED  BY 


Ward's  Steam  for  the  Million. 

New  and  Revised  Edition. 

8vo.  Cloth.    $1.00. 

STEAM  FOE  THE  MILLION.  A  Popular  Treatise  on  Steam 
and  its  Application  to  the  Useful  Arts,  especially  to  Naviga 
tion.  By  J.  H.  WARD,  Commander  U.  S.  Navy.  New  and  re 
vised  edition. 

A  most  excellent  work  for  the  young1  engineer  and  general  reader.  Many 
facts  relating  to  the  management  of  the  boiler  and  engine  are  set  forth  with  a 
simplicity  of  language  and  perfection  of  detail  that  bring  the  subject  home 
to  the  reader. — American  Engineer. 


Walker's  Screw  Propulsion. 

8vo.     Cloth.     75  cents. 

:    •   , 

NOTES  ON  SCEEW  PKOPULSION,  its  Bise  and  History.     By 
Capt.  W.  H.  WALKER,  U.  S.  Navy. 

Commander  Walker's  book  contains  an  immense  amount  of  concise  practi 
cal  data,  and  every  item  of  information  recorded  fully  proves  that  the  various 
points  bearing  upon  it  have  been  well  considered  previously  to  expressing  an 
opinion. — London  Mining  Journal. 


Page's  Earth's  Crust. 

18mo.     Cloth.     75  cents. 

THE  EAETH'S  CRUST :    a   Handy   Outline   of  Geology.      By 
DAVID  PAGE. 

"  Such  a  work  as  this  was  much  wanted — a  work  giving  in  clear  and  intel 
ligible  outline  the  leading  facts  of  the  science,  without  amplification  or  irk 
some  details.  It  is  admirable  in  arrangement,  and  clear  and  easy,  and,  at  the 
same  time,  forcible  in  style.  It  will  lead,  we  hope,  to  the  introduction  of 
Geology  into  many  schools  that  have  neither  time  nor  room  for  the  study  of 
large  treatises." — TTie  Museum. 


D.  VAN  NOSTRA&D.  31 


Rogers'  Geology  of  Pennsylvania. 

3  Vol«.  4to,  with  Portfolio  of  Maps.     Cloth.     $30.00. 

THE  GEOLOGY  OF  PENNSYLVANIA.  A  Government  Sur 
vey.  With  a  general  view  of  the  Geology  of  the  United  States, 
Essays  on  the  Coal  Formation  and  its  Fossils,  and  a  description 
of  the  Coal  Fields  of  North  America  and  Great  Britain.  By 
HENRY  DARWIN  ROGERS,  Late  State  Geologist  of  Pennsylvania. 
Splendidly  illustrated  with  Plates  and  Engravings  in  the  Text. 

It  certainly  should  be  in  every  public  library  trough  out  the  country,  and 
likewise  in  the  possession  of  all  students  of  Geology.  After  the  final  sale  of 
these  copies,  the  work  will,  of  course,  become  more  valuable. 

The  work  for  the  last  five  years  has  been  entirely  out  of  the  market,  but  a 
few  copies  that  remained  in  the  hands  of  Prof.  Rogers,  in  Scotland,  at  the 
time  of  his  death,  are  now  offered  to  the  public,  at  a  price  which  is  even 
below  what  it  was  originally  sold  for  when  first  published. 


Morfit  on  Pure  Fertilizers. 

With  28  Illustrative  Plates.     8vo.     Cloth.     $20.00. 

A  PRACTICAL  TREATISE  ON  PURE  FERTILIZERS,  and 
the  Chemical  Conversion  of  Rock  Guanos,  Marlstones,  Coprolites, 
and  the  Crude  Phosphates  of  Lime  and  Alumina  Generally,  into 
various  Valuable  Products.  By  CAMPBELL  MORFIT,  M.D.,  F.C.S. 


Sweet's  Report  on  Coal. 

8vo.    Cloth.     $3.00. 

SPECIAL  REPORT  ON  COAL  ;  showing  its  Distribution,  Classi 
fication,  and  Cost  delivered  over  different  routes  to  various  points 
in  the  State  of  New  York,  and  the  principal  cities  on  the  Atlantic    ' 
Coast     By  S.  H.  SWEET.     With  maps. 


Colburn's  Gas  Works  of  London. 

13mo.     Boards.     60  cents. 
GAS  WORKS  OF  LONDON.     By  ZERAH  COLBUEN. 


32  SCIENTIFIC  BOOKS  PUBLISHED  BY 

The  Useful  Metals  and  their  Alloys ; 
Scoffren,  Trnran,  and  others. 

Fifth  Edition. 

8vo.     Half  calf.     $3.75. 

THE  USEFUL  METALS  AND  THEIR  ALLOYS,  including 
MINING  VENTILATION,  MINING  JURISPRUDENCE 
AND  METALLURGIC  CHEMISTRY  employed  in  the  conver 
sion  of  IRON,  COPPER,  TIN,  ZINC,  ANTIMONY,  AND 
LEAD  ORES,  with  their  applications  to  THE  INDUSTRIAL 
ARTS.  By  JOHN  SCOFFREN,  WILLIAM  TRURAN,  WILLIAM  CLAY, 
ROBERT  Ox  LAND,  WILLIAM  FAIRBAIRN,  W.  C.  AITKIN,  and  WIL 
LIAM  VOSE  PICXETT. 


Collins1  Useful  Alloys. 

18mo.     Flexible.     75  cents. 

THE  PRIVATE  BOOK  OF  USEFUL  ALLOYS  and  Memo 
randa  for  Goldsmiths,  Jewellers,  etc.  By  JAMES  E.  COLLINS 

This  little  book  is  compiled  from  notes  made  by  the  Author  from  the 
papers  of  one  of  the  largest  and  most  eminent  Manufacturing  Goldsmiths  and 
Jewellers  in  this  country,  and  as  the  firm  is  now  no  longer  in  existence,  and  the 
Author  is  at  present  engaged  in  some  other  undertaking,  he  now  offers  to  the 
public  the  benefit  of  his  experience,  and  in  so  doing  he  begs  to  state  that  all 
-the  alloys,  etc.,  given  in  these  pages  may  be  confidently  relied  on  as  being 
thoroughly  practicable. 

The  Memoranda  and  Receipts  throughout  this  book  are  also  compiled 
from  practice,  and  will  no  doubt  be  found  useful  to  the  practical  jeweller. 
—Shirley,  July,  1871.  

Joynson's  Metals  Used  in  Construction. 

12mo.    Cloth.     75  cents. 

THE  METALS  USED  IN  CONSTRUCTION:  Iron,  Steel, 
Bessemer  Metal,  etc.,  etc.  By  FRANCIS  HERBERT  JOYNSON.  Il 
lustrated. 

"  In  the  interests  of  practical  science,  we  are  bound  to  notice  this  work  ; 
and  to  those  who  wish  further  information,  we  should  say,  buy  it ;  and  the 
outlay,  we  honestly  believe,  will  be  considered  well  spent."  —  Scientific 
Review. 


D.   VAN  N08THAND.  33 


Holley's  Ordnance  and  Armor. 

493  Engravings.     Half  Roan,  $10.00.     Half  Russia,  $12.00. 

A  TREATISE  ON  ORDNANCE  AND  ARMOR— Embracing 
Descriptions,  Discussions,  and  Professional  Opinions  concerning 
the  MATERIAL,  FABRICATION,  Requirements,  Capabilities,  and  En 
durance  of  European  and  American  Guns,  for  Naval,  Sea  Coast, 
and  Iron-clad  Warfare,  and  their  RIFLING,  PROJECTILES,  and 
BREECH-LOADING;  also,  Results  of  Experiments  against  Armor, 
from  Official  Records,  with  an  Appendix  referring  to  Gun-Cotton, 
Hooped  Guns,  etc.,  etc.  By  ALEXANDER  L.  HOLLET,  B.  P.  948 
pages,  493  Engravings,  and  147  Tables  of  Results,  etc. 

CONTENTS. 

CHAPTER  I. — Standard  Guns  and  their  Fabrication  Described :  Section  1. 
Hooped  Guns ;  Section  2.  Solid  Wrought  Iron  Guns ;  Section  3.  Solid  Steel 
Guns ;  Section  4.  Cast-Iron  Guns,  CHAPTER  II. — The  Requirements  of  Guns, 
Armor:  Section  1.  The  Work  to  be  done;  Section  2.  Heavy  Shot  at  Low  Ve 
locities;  SectionS.  Small  Shot  at  High  Velocities;  Section  4.  The  two  Sys 
tems  Combined ;  Section  5.  Breaching  Masonry.  CHAPTER  III. — The  Strains 
and  Structure  of  Guns:  Section  1.  Resistance  to  Elastic  Pressure;  Section  2. 
The  Effects  of  Vibration;  Section  3.  The  Effects  of  Heat.  CHAPTER  IV.-— 
Cannon  Metals  and  Processes  of  Fabrication:  Section  1.  Elasticity  and  Ductil 
ity;  Section  2.  Cast-Iron;  Section  3.  Wrought  Iron;  Section  4.  Steel;  Sec 
tion  5.  Bronze ;  Section  6.  Other  Alloys.  CHAPTER  V. — Rifling  and  Projec 
tiles  ;  Standard  Forms  and  Practice  Described ;  Early  Experiments ;  The 
Centring  System  ;  The  Compressing  System ;  The  Expansion  System ;  Armor 
Punching  Projectiles;  Shells  for  Molten  Metal;  Competitive  Trial  of  Rifled 
Guns,  1802;  Duty  of  Rifled  Guns:  General  Uses,  Accuracy,  Range,  Velocity, 
Strain,  Liability  of  Projectile  to  Injury ;  Firing  Spherical  Shot  from  Rifled 
Guns ;  Material  for  Armor-Punching  Projectiles ;  Shape  of  Armor-Punching 
Projectiles ;  Capacity  and  Destructiveness  of  Shells ;  Elongated  Shot  from 
Smooth  Bores;  Conclusions;  Velocity  of  Projectiles  (Table  .  CHAPTER  VI.— 
Breech-Loading  Advantages  and  Defects  of  the  System;  Rapid  Firing  and 
Cooling  Guns  by  Machinery ;  Standard  Breech-Loaders  Described.  Part  Sec 
ond  :  Experiments  against  Armor ;  Account  of  Experiments  from  Official 
Records  in  Chronological  Order.  APPENDIX. — Report  on  the  Application  of 
Gun-Cotton  to  Warlike  Purposes — British  Association,  18G3;  Manufacture  and 
Experiments  in  England ;  Guns  Hooped  with  Initial  Tension — History;  How 
Guns  Burst,  by  Wiard,  Lyman's  Accelerating  Gun;  Endurance  of  Parrott 
and  Whitworth  Guns  at  Charleston  ;  Hooping  old  United  States  Cast-Iron 
Guns  ;  Endurance  and  Accuracy  of  the  Armstrong  600-pounder ;  Competitive 
Trials  with  7-inch  Guns. 


34          SCIENTIFIC  BOOKS  PUBLISHED  BY 

1 

Peirce's  Analytic  Mechanics. 

4*©.    Cloth.    $10.00. 

SYSTEM  OF  ANAJLYT1C  MECHANICS.  Physical  and  Celestial 
Mechanics.  By  BENJAMIN  PEIRCE,  Perkins  Professor  of  Astronomy 
and  Mathematics  in  Harvard  University,  and  Consulting  As 
tronomer  of  the  American  Ephemeris  and  Nautical  Almanac. 
Developed  in  four  systems  of  Analytic  Mechanic^  Celestial 
Mechanics,  Potential  Physics>  and  Analytic  Morphology. 

*'  I  hare  re-examined  the  memoirs  of  the  great  geometers,  and  hare  striven 
to  consolidate  their  latest  researches  and  their  most  exalted  forms  of  thought 
into  a  consistent  and  uniform  treatise.  If  I  have  hereby  succeeded  in  open 
ing  to  the  students  of  my  country  a  readier  access  to  these  choice  jewels  of 
intellect ;  if  their  brilliancy  is  not  impaired  in  this  attempt  to  reset  them ;  if, 
in  their  own  constellation,  they  illustrate  each  other,  and  concentrate 
a  stronger  light  tzpon  the  names  of  their  discoverers  ,  and,  still  more,  if  any 
gem  which  I  may  have  presumed  to  add  is  not  wholly  lustreless  in  the  collec 
tion,  I  shall  feel  that  my  work  has  a.ot  beea  in  vain."-J£artro$*  from  the  Pre 
face. 

Burt's  Key  to  Solar  Compass. 

Second  Edition. 

Pocket  Book  Form.     Tuck.    $2.50. 

KEY  TO  THE  SOLAR  COMPASS,  and  Surveyor's-  Companion ; 
comprising  all  the  Rules  necessary  for  use  in  the  field;  also, 
Description  of  the  Linear  Surveys  and  Public  Land  System  of 
the  United  States,  Notes  on  the  Barometer,  Suggestions  for  an 
outfit  for  a  Survey  of  four  months,  etc.,  etc.,  etc.  By  W.  A. 
BUKT,  U.  S.  Deputy  Surveyor.  Second  edition. 


ChauYenet's  Lunar  Distances. 

8r<x.    Cloth.    $2,00. 

NEW  METHOD  OF  CORRECTING  LUNAR  DISTANCES, 
and  Improved  Method  of  Finding  the  Error  and  Rate  of  a  Chro 
nometer,  by  equal  altitudes.  By  WM.  CHAUVENET,  LL.D.,  Chan 
cellor  of  Washington  University  of  St.  Louis. 


D.   VAN  NOSTRAND.  35 


Jeffers'  Nautical  Surveying. 

Illustrated  with  9  Copperplates  and  31  Wood-cut  Illustrations.     8vo. 
Cloth.     $5.00. 

NAUTICAL  SURVEYING.  By  WILUAM  N.  JEFFEKS,  Captain 
U.  S.  Navy. 

Many  books  have  been  written  on  each  of  the  subjects  treated  of  in  the 
sixteen  chajrters  of  this  work;  and,  to  obtain  a  complete  knowledge  of 
geodetic  surveying  requires  a  profound  study  of  the  whole  range  of  mathe 
matical  and  physical  sciences ;  but  a  year  of  preparation  should  render  any 
intelligent  officer  competent  to  conduct  a.  nautical  survey. 

CONTENTS. — Chapter  I.  Formulae  and  Constants  Useful  in  Surveying 
II.  Distinctive  Character  of  Surveys.  III.  Hydrographic  Surveying  under 
Sail ;  or,  Running  Survey.  IV.  Hydrographic  Surveying  of  Boats ;  or,  Har 
bor  Survey.  V.  Tides — Definition  of  Tidal  Phenomena — Tidal  Observations. 
VI.  Measurement  of  Bases — Appropriate  and  Direct.  VII.  Measurement  of 
the  Angles  of  Triangles — Azimuths — Astronomical  Bearings.  VIII.  Correc 
tions  to  be  Applied  to  the  Observed  Angles.  IX.  Levelling — Difference  of 
Level.  X.  Computation  of  the  Sides  of  the  Triangulation — The  Three-point 
Problem.  XI.  Determination  of  the  Geodetic  Latitudes,  Longitudes,  and 
Azimuths,  of  Points  of  a  Triangulation.  XII.  Summary  of  Subjects  treated 
of  in  preceding  Chapters — Examples  of  Computation  by  various  Formulae. 
XIII.  Projection  of  Charts  and  Plans.  XIV.  Astronomical  Determination  of 
Latitude  and  Longitude.  XV.  Magnetic  Observations.  XVI.  Deep  Sea 
Soundings.  XVII.  Tables  for  Ascertaining  Distances  at  Sea,  and  a  full 
Index. 

List  of  Plates. 

Plate  I.  Diagram  Illustrative  of  the  Triangulation.  II.  Specimen  Page 
of  Field  Book.  III.  Running  Survey  of  a  Coast.  IV.  Example  of  a  Running 
Survey  from  Belcher.  V.  Flying  Survey  of  an  Island.  VI.  Survey  of  a 
ShoaL  VII.  Boat  Survey  of  a  River.  VIII.  Three-Point  Problem.  IX. 
Triangulation. 

Coffin's  Navigation. 

Fifth  Edition. 

12mo.     Cloth.     $3.50. 

NAVIGATION  AND  NAUTICAL  ASTEONOMY.  Prepared 
for  the  use  of  the  U.  S.  Naval  Academy.  By  J.  H.  C.  COFFIN, 
Prof,  of  Astronomy,  Navigation  and  Surveying,  with  52  wood 
cut  illustrations. 


36  SCIENTIFIC  BOOKS  PUBLISHED  13 Y 

Clark's  Theoretical  Navigation. 

8yo.     Cloth.     $3.00. 

THEORETICAL  NAVIGATION  AND  NAUTICAL  ASTRON- 
OMY.  By  LEWIS  CLARK,  Lieut. -Commander,  U.  S.  Navy.  Il 
lustrated  with  41  Wood-cuts,  including  the  Vernier. 

Prepared  for  Use  at  the  U.  S.  Naval  Academy. 


The  Plane  Table. 

Illustrated.    8vo.     Cloth.     $2.00. 

ITS  USES  IN  TOPOGRAPHICAL  SURVEYING.     From  the 
Papers  of  the  U.  S.  Coast  Survey. 

This  work  gives  a  description  of  the  Plane  Table  employed  at  the  U.  S. 
Coast  Survey  Office,  and  the  manner  of  using  it. 


Pook  on  Shipbuilding. 

8vo.    Cloth.     $5.00. 

METHOD  OF  COMPARING  THE  LINES  AND  DRAUGHT 
ING  VESSELS  PROPELLED  BY  SAIL  OR  STEAM,  in 
cluding  a  Chapter  on  Laying  off  on  the  Mould-Loft  Floor.  By 
SAMUEL  M.  POOK,  Naval  Constructor.  1  vol.,  8vo.  With  illus 
trations.  Cloth.  $5.00. 


Brunnow's  Spherical  Astronomy. 

8vo.     Cloth.     $6.50. 

SPHERICAL  ASTRONOMY.     By  F.  BRUSWOW,  Ph.  Dr.    Trans 
lated  by  the  Author  from  the  Second  German  edition. 


I>.  VAN  NO  STRAND. 


Van  Buren's  Formulas. 

8vo.    Cloth.     $2.00. 

INVESTIGATIONS  OF  FOKMULAS,  for  the  Strength  of  the 
Iron  Parts  of  Steam  Machinery.  By  J.  D.  VAN  BUREN,  Jr.,  C.  E. 
Illustrated. 

This  is  an  analytical  discussion  of  the  formulae  employed  by  mechanical 
engineers  in  determining  the  rupturing  or  crippling  pressure  in  the  different 
parts  of  a  machine.  The  formulae  are  founded  upon  the  principle,  that  the 
different  parts  of  a  machine  should  be  equally  strong,  and  are  developed  in 
reference  to  the  ultimate  strength  of  the  material  in  order  to  leave  the  choico 
of  a  factor  of  safety  to  the  judgment  of  the  designer.— Silli man's  Journal. 


Joynson  on  Machine  Gearing. 

8vo.     Cloth.     $2.00. 

THE  MECHANIC'S  AND  STUDENT'S  GUIDE  in  the  Design 
ing  and  Construction  of  General  Machine  Gearing,  as  Eccentrics, 
Screws,  Toothed  Wheels,  etc.,  and  the  Drawing  of  Eectilineal 
and  Curved  Surfaces  ;  with  Practical  Rules  and  Details.  Edited 
by  FRANCIS  HERBERT  JOYNSON.  Illustrated  with  18  folded 
plates. 

"  The  aim  of  this  work  is  to  be  a  guide  to  mechanics  in  the  designing  and 
construction  of  general  machine-gearing.  This  design  it  well  fulfils,  being 
plainly  and  sensibly  written,  and  profusely  illustrated." — Sunday  Times. 


Barnard's  Report,  Paris  Exposition, 

1867. 

Illustrated.     8vo.     Cloth.     $5.00. 

REPORT  ON  MACHINERY  AND  PROCESSES  ON  THE 
INDUSTRIAL  ARTS  AND  APPARATUS  OF  THE  EXACT 
SCIENCES.  By  F.  A.  P.  BARNARD,  LL.D.— Paris  Universal 
Exposition,  1867. 

"  We  have  in  this  volume  the  results  of  Dr.  Barnard's  study  of  the  Paris 
Exposition  of  1867,  in  the  form  of  an  official  Beport  of  the  Government.  It 
is  the  most  exhaustive  treatise  upon  modern  inventions  that  has  appeared 
since  the  Universal  Exhibition  of  1851,  and  we  doubt  if  anything  equal  to  it 
has  appeared  this  century."— Journal  Applied  Chemistry. 


38  SCIENTIFIC  BOOKS  PUBLISHED  BY 

Engineering  Facts  and  Figures. 

18mo.     Cloth.     $2.50  per  Volume. 

AN  ANNUAL  EEGISTEE  OF  PEOGEESS  IN  MECHANI 
CAL  ENGINEEEING  AND  CONSTEUCTION,  for  the  Years 
1863-64-65-66-67-68.  Fully  illustrated.  6  volumes. 

Each  volume  sold  separately. 


Beckwith's  Pottery. 

8vo.    Paper.    60  cents. 

OBSEEVATIONS  ON  THE  MATEEIALS  and  Manufacture  of 
Terra-Cotta,  Stone-Ware,  Fire-Brick,  Porcelain  and  Encaustic 
Tiles,  with  Eemarks  on  the  Products  exhibited  at  the  London 
International  Exhibition,  1871.  By  ARTHUR  BECK  WITH,  Civil 
Engineer. 

"  Everything  is  noticed  in  this  book  which  comes  under  the  head  of  Pot 
tery,  from  fine  porcelain  to  ordinary  brick,  and  aside  from  the  interest  which 
all  take  in  such  manufactures,  the  work  will  be  of  considerable  value  to 
followers  of  the  ceramic  art." — Evening  Mail. 


Dodd's  Dictionary  of  Manufactures,  etc. 

12mo.     Cloth.     $2.00. 

DICTIONAEY  OF   MANUFACTUEES,   MINING,   MACHIN- 
EEY,  AND  THE  INDUSTEIAL  AETS.     By  GEORGE  DSDD. 

This  work,  a  small  book  on  a  great  subject,  treats,  in  alphabetical  ar 
rangement,  of  those  numerous  matters  which  come  generally  within  the  range 
of  manufactures  and  the  productive  arts.  The  raw  materials — animal,  vege 
table,  and  mineral — whence  the  manufactured  products  are  derived,  are  suc 
cinctly  noticed  in  connection  with  the  processes  which  they  undergo,  but  not 
as  subjects  of  natural  history.  The  operations  of  the  Mine  and  the  Mill,  the 
Foundry  and  the  Forge,  the  Factory  and  the  Workshop,  are  passed  under  re 
view.  The  principal  machines  and  engines,  tools  and  apparatus,  concerned  in 
manufacturing  processes,  are  briefly  described.  The  scale  on  which  our  chief 
branches  of  national  industry  are  conducted,  in  regard  to  values  and  quantities, 
is  indicated  in  various  ways. 


D.    VAN  NOST11AND.  39 


Stuart's  Civil  and  Military  Engineer 
ing  of  America. 

8vo.     Illustrated.     Cloth.     $5.00. 

THE  CIVIL  AND  MILITAEY  ENGINEERS  OF  AMEEICA. 
By  General  CHARLES  B.  STUART,  Author  of  "  Naval  Dry  Docks 
of  the  United  States,"  etc.,  etc.  Embellished  with  nine  finely 
executed  portraits  on  steel  of  eminent  engineers,  and  illustrated 
by  engravings  of  some  of  the  most  important  and  original  worlds 
constructed  in  America. 

Containing  sketches  of  the  Life  and  "Works  of  Major  Andrew  Ellicott, 
James  Geddes  (with  Portrait  ,  Benjamin  Wright  (with  Portrait),  Canvass 
White  (with  Portrait),  David  Stanhope  Bates,  Nathan  S.  Roberts,  Gridley 
Bryant  (with  Portrait),  General  Joseph  G.  Swift,  Jesse  L.  Williams  (with 
Portrait),  Colonel  William  McE.ee,  Samuel  H.  Kneass,  Captain  John  Childe 
with  Portrait',  Frederick  Harbach,  Major  David  Bates  Douglas  -with  Por 
trait),  Jonathan  Knight,  Benjamin  II.  Latrobe  (with  Portrait),  Colonel  Char 
les  Ellet,  Jr.  vwith  Portrait),  Samuel  Forrer,  William  Stuart  Watson,  John 
A.  Roebling. 


Alexander's  Dictionary  of  Weights 
and  Measures. 

8vo.     Cloth.     $3.50. 

UNIVERSAL  DICTIONARY  OF  WEIGHTS  AND  MEAS 
URES,  Ancient  and  Modern,  reduced  to  the  standards  of  the 
United  States  of  America.  By  J.  H.  ALEXANDER.  New  edition. 
1  vol. 

"  As  a  standard  work  of  reference,  this  book  should  be  in  every  library ;  it 
is  one  which  we  have  long  wanted,  and  it  will  save  much  trouble  and  re 
search." — Scientific  American. 


Gouge  on  Ventilation. 

Third  Edition  Enlarged. 

8vo.     Cloth.     $2.00. 

NEW  SYSTEM  OF  VENTILATION,  which  has  been  thoroughly 
tested  under  the  patronage  of  many  distinguished  persons.  By 
HENRY  A.  GOUGE,  with  many  illustrations. 


40  SCIENTIFIC  BOOKS  PUBLISHED  B  Y 

Saeltzer's  Acoustics. 

12mo.     Cloth.     $2.00. 

TREATISE  ON  ACOUSTICS  in  Connection  with  Ventilation. 
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ing  clear  and  intelligible  sound  in  any  building.  By  ALEXANDER 
SAELTZER. 

"  A  practical  and  very  sound  treatise  on  a  subject  of  great  importance  to 
architects,  and  one  to  -which  there  has  hitherto  been  entirly  too  little  attention 
paid.  The  author's  theory  is,  that,  by  bestowing  proper  care  upon  the  point 
of  Acoustics,  the  requisite  ventilation  will  be  obtained,  and  vice  versa. — 
Brooklyn  Union. 


Myer's  Manual  of  Signals. 

New  Edition.    Enlarged. 

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MANUAL  OF  SIGNALS,  for  the  Use  of  Signal  Officers  in  the 
Field,  and  for  Military  and  Naval  Students,  Military  Schools, 
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ALBERT  J.  MYER,  Chief  Signal  Officer  of  the  Army,  Colonel  of 
the  Signal  Corps  during  the  War  of  the  Rebellion. 


Larrabee's  Secret  Letter  and 
Telegraph.  Code. 

18mo.     Cloth.     $1.00. 

CIPHER  AND  SECRET  LETTER  AND  TELEGRAPHIC 
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the  Key.  Invaluable  for  Secret,  Military,  Naval,  and  Diplo 
matic  Service,  as  well  as  for  Brokers,  Bankers,  and  Merchants. 
By  C.  S.  LARRABEE,  the  original  inventor  of  the  scheme. 


D.   VAN  NOSTRAND.  41 


Hunt's  Designs  for  Central  Park 
Gateways. 

4to.     Cloth.     $5.00. 

DESIGNS  FOR  THE  GATEWAYS  OF  THE  SOUTHERN 
ENTRANCES  TQ  THE  CENTRAL  PARK.  By  RICHABD  M. 
HUNT.  With  a  description  of  the  designs. 


Pickert  and  Metcalf  s  Art  of  Graining. 

1  vol.     4to.     Cloth.     $10.00. 

THE  ART  OF  GRAINING.  How  Acquired  and  How  Produced, 
with  description  of  colors  and  their  application.  By  CHABLES 
PICKERT  and  ABRAHAM  METCALF.  Beautifully  illustrated  with  42 
tinted  plates  of  the  various  woods  used  in  interior  finishing. 
Tinted  paper. 

The  authors  present  here  the  result .  of  long  experience  in  the  practice  of 
this  decorative  art,  and  feel  confident  that  they  hereby  offer  to  their  brother 
artisans  a  reliable  guide  to  improvement  in  the  practice  of  graining. 


Portrait  Gallery  of  the  War. 

60  fine  Portraits  on  Steel.     Royal  8vo.    Cloth.     $6.00. 

PORTRAIT  GALLERY  OF  THE  WAR,  CIVIL,  MILITARY 
AND  NAVAL.  A  Biographical  Record.  Edited  by  FRANK 
MOORE. 


One  Law  in  Nature. 

12mo.    Cloth.    $1.50. 

ONE  LAW  IN  NATURE.  By  Capt.  H.  M.  LAZELLE,  U.  S.  A. 
A  New  Corpuscular  Theory,  comprehending  Unity  of  Force, 
Identity  of  Matter,  and  its  Multiple  Atom  Constitution,  applied 
to  the  Physical  Affections  or  Modes  of  Energy. 


42  SCIENTIFIC  BOOKS  PUBLISHED  BY 


West  Point  Scrap  Book. 

69  Engravings  and  Map.     8vo.     Extra  Cloth.     $5.00. 
WEST  POINT  SCEAP  BOOK.     Being  a  Collection  of  LEGENDS, 
STORIES,  SONGS,  ETC.,  of  the  U.  S.  Military  Academy.  By  Lieut.  0. 
E.  WOOD,  U.  S.  A.     Beautifully  printed  on  tinted  paper. 

"  It  is  the  work  of  several  different  writers,  whose  names  are  withheld  from 
the  public,  but  whose  contributions  all  bear  a  decided  flavor  of  their  origin, 
preserving  the  unity  of  a  military  education  and  experience.  The  volume 
abounds  with  personal  anecdotes  and  humorous  narratives,  seasoned  with 
copious  specimens  of  the  students'  songs,  and  presenting  a  vivid,  and  doubtless 
a  faithful,  exhibition  of  the  peculiar  lights  and  shades  of  West  Point  life." — 
N.  T.  Tribune.  

History  of  West  Point. 

Second  Edition. 

With  36  Illustrations  and  Maps.     8vo.     Extra  Cloth.     $3.50. 
HISTORY  OF  WEST  POINT.     Its  Military  Importance  during 
the  American  He  volution,  and  the  Origin  and  Progress  of  the  U. 
"S.  Military  Academy.      By   Bvt. -Major   E.    C.    BOTNTON.     416 
pages.     Printed  on  tinted  paper. 

"  Aside  from  its  value  as  an  historical  record,  the  volume  under  notice  is  an 
entertaining  guide-book  to  the  Military  Academy  and  its  surroundings.  "We 
have  full  details  of  Cadet  life  from  the  day  of  entrance  to  that  of  graduation, 
together  with  descriptions  of  the  buildings,  grounds  and  monuments.  To 
the  multitude  of  those  who  have  enjoyed  at  West  Point  the  combined  attrac 
tions,  this  book  will  give,  in  its  descriptive  and  illustrated  portion,  especial 
pleasure." — New  York  Evening  Post. 


West  Point  Life, 

Oblong  8vo.     21  full-page  Illustrations.     Cloth.    $2.50. 
WEST  POINT  LIFE.     A  Poem  read  before  the  Dialectic  Society 
of  the   United  States  Military  Academy.     Illustrated  with  Pen 
and  Ink  Sketches.     By  A  CADET.     To  which  is  added  the  song 
"  Benny  Havens,  Oh  !  " 

"  Summer  visitors  at  West  Point  will  especially  enjoy  these  illustrations  ; 
and  the  poem  itself  may  be  regarded  as  a  description  of  Cadet  life,  as  seen 
from  the  inside,  by  one  who  appreciates  it." — N.  Y.  Journal  of  Commerce. 


Guide  to  West  Point 

and  the   U.    S.   Military  Academy,   with  Maps   and  Engravings. 
18mo.     Blue  Cloth.     Flexible  Covers.     $1.00. 


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